Permutation and Combination Foundations

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This question bank has corresponding bilingual step-by-step derivations. Source candidate and English ai_candidate states are retained. AI review, finite computation and Lean formal proof are labelled separately.

batch-20260930-r06-permutation-combination-foundations · 2026-09-30 · 100 questions

This English edition is an AI candidate and does not yet have an OCME Atlas (GPT-6) Twin closure receipt.

1. Exact Ordered Selection Count

Select k=0 objects in order, without replacement or repetition, from n=0 distinct objects. The empty selection counts once. Find P(0,0).

View answer and explanation

1

Multiply the successive available-choice counts exactly to obtain 1; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

2. Exact Ordered Selection Count

Select k=1 objects in order, without replacement or repetition, from n=1 distinct objects. The empty selection counts once. Find P(1,1).

View answer and explanation

1

Multiply the successive available-choice counts exactly to obtain 1; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

3. Exact Ordered Selection Count

Select k=0 objects in order, without replacement or repetition, from n=2 distinct objects. The empty selection counts once. Find P(2,0).

View answer and explanation

1

Multiply the successive available-choice counts exactly to obtain 1; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

4. Exact Ordered Selection Count

Select k=2 objects in order, without replacement or repetition, from n=2 distinct objects. The empty selection counts once. Find P(2,2).

View answer and explanation

2

Multiply the successive available-choice counts exactly to obtain 2; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

5. Exact Ordered Selection Count

Select k=1 objects in order, without replacement or repetition, from n=3 distinct objects. The empty selection counts once. Find P(3,1).

View answer and explanation

3

Multiply the successive available-choice counts exactly to obtain 3; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

6. Exact Ordered Selection Count

Select k=3 objects in order, without replacement or repetition, from n=3 distinct objects. The empty selection counts once. Find P(3,3).

View answer and explanation

6

Multiply the successive available-choice counts exactly to obtain 6; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

7. Exact Ordered Selection Count

Select k=2 objects in order, without replacement or repetition, from n=4 distinct objects. The empty selection counts once. Find P(4,2).

View answer and explanation

12

Multiply the successive available-choice counts exactly to obtain 12; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

8. Exact Ordered Selection Count

Select k=4 objects in order, without replacement or repetition, from n=4 distinct objects. The empty selection counts once. Find P(4,4).

View answer and explanation

24

Multiply the successive available-choice counts exactly to obtain 24; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

9. Exact Ordered Selection Count

Select k=0 objects in order, without replacement or repetition, from n=5 distinct objects. The empty selection counts once. Find P(5,0).

View answer and explanation

1

Multiply the successive available-choice counts exactly to obtain 1; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

10. Exact Ordered Selection Count

Select k=1 objects in order, without replacement or repetition, from n=5 distinct objects. The empty selection counts once. Find P(5,1).

View answer and explanation

5

Multiply the successive available-choice counts exactly to obtain 5; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

11. Exact Ordered Selection Count

Select k=2 objects in order, without replacement or repetition, from n=5 distinct objects. The empty selection counts once. Find P(5,2).

View answer and explanation

20

Multiply the successive available-choice counts exactly to obtain 20; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

12. Exact Ordered Selection Count

Select k=5 objects in order, without replacement or repetition, from n=5 distinct objects. The empty selection counts once. Find P(5,5).

View answer and explanation

120

Multiply the successive available-choice counts exactly to obtain 120; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

13. Exact Ordered Selection Count

Select k=1 objects in order, without replacement or repetition, from n=6 distinct objects. The empty selection counts once. Find P(6,1).

View answer and explanation

6

Multiply the successive available-choice counts exactly to obtain 6; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

14. Exact Ordered Selection Count

Select k=3 objects in order, without replacement or repetition, from n=6 distinct objects. The empty selection counts once. Find P(6,3).

View answer and explanation

120

Multiply the successive available-choice counts exactly to obtain 120; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

15. Exact Ordered Selection Count

Select k=6 objects in order, without replacement or repetition, from n=6 distinct objects. The empty selection counts once. Find P(6,6).

View answer and explanation

720

Multiply the successive available-choice counts exactly to obtain 720; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

16. Exact Ordered Selection Count

Select k=2 objects in order, without replacement or repetition, from n=7 distinct objects. The empty selection counts once. Find P(7,2).

View answer and explanation

42

Multiply the successive available-choice counts exactly to obtain 42; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

17. Exact Ordered Selection Count

Select k=4 objects in order, without replacement or repetition, from n=7 distinct objects. The empty selection counts once. Find P(7,4).

View answer and explanation

840

Multiply the successive available-choice counts exactly to obtain 840; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

18. Exact Ordered Selection Count

Select k=7 objects in order, without replacement or repetition, from n=7 distinct objects. The empty selection counts once. Find P(7,7).

View answer and explanation

5040

Multiply the successive available-choice counts exactly to obtain 5040; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

19. Exact Ordered Selection Count

Select k=0 objects in order, without replacement or repetition, from n=8 distinct objects. The empty selection counts once. Find P(8,0).

View answer and explanation

1

Multiply the successive available-choice counts exactly to obtain 1; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

20. Exact Ordered Selection Count

Select k=3 objects in order, without replacement or repetition, from n=8 distinct objects. The empty selection counts once. Find P(8,3).

View answer and explanation

336

Multiply the successive available-choice counts exactly to obtain 336; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

21. Exact Ordered Selection Count

Select k=8 objects in order, without replacement or repetition, from n=8 distinct objects. The empty selection counts once. Find P(8,8).

View answer and explanation

40320

Multiply the successive available-choice counts exactly to obtain 40320; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

22. Exact Ordered Selection Count

Select k=1 objects in order, without replacement or repetition, from n=9 distinct objects. The empty selection counts once. Find P(9,1).

View answer and explanation

9

Multiply the successive available-choice counts exactly to obtain 9; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

23. Exact Ordered Selection Count

Select k=4 objects in order, without replacement or repetition, from n=9 distinct objects. The empty selection counts once. Find P(9,4).

View answer and explanation

3024

Multiply the successive available-choice counts exactly to obtain 3024; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

24. Exact Ordered Selection Count

Select k=5 objects in order, without replacement or repetition, from n=10 distinct objects. The empty selection counts once. Find P(10,5).

View answer and explanation

30240

Multiply the successive available-choice counts exactly to obtain 30240; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

25. Exact Ordered Selection Count

Select k=6 objects in order, without replacement or repetition, from n=12 distinct objects. The empty selection counts once. Find P(12,6).

View answer and explanation

665280

Multiply the successive available-choice counts exactly to obtain 665280; when k=0 the empty product is 1.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-exact-count · candidate

26. Exact Unordered Selection Count

Select k=0 objects without order, replacement, or repetition from n=0 distinct objects. The empty selection counts once. Find C(0,0).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

27. Exact Unordered Selection Count

Select k=1 objects without order, replacement, or repetition from n=1 distinct objects. The empty selection counts once. Find C(1,1).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

28. Exact Unordered Selection Count

Select k=0 objects without order, replacement, or repetition from n=2 distinct objects. The empty selection counts once. Find C(2,0).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

29. Exact Unordered Selection Count

Select k=2 objects without order, replacement, or repetition from n=2 distinct objects. The empty selection counts once. Find C(2,2).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

30. Exact Unordered Selection Count

Select k=1 objects without order, replacement, or repetition from n=3 distinct objects. The empty selection counts once. Find C(3,1).

View answer and explanation

3

Count the k-element subsets exactly to obtain 3; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

31. Exact Unordered Selection Count

Select k=3 objects without order, replacement, or repetition from n=3 distinct objects. The empty selection counts once. Find C(3,3).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

32. Exact Unordered Selection Count

Select k=2 objects without order, replacement, or repetition from n=4 distinct objects. The empty selection counts once. Find C(4,2).

View answer and explanation

6

Count the k-element subsets exactly to obtain 6; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

33. Exact Unordered Selection Count

Select k=4 objects without order, replacement, or repetition from n=4 distinct objects. The empty selection counts once. Find C(4,4).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

34. Exact Unordered Selection Count

Select k=0 objects without order, replacement, or repetition from n=5 distinct objects. The empty selection counts once. Find C(5,0).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

35. Exact Unordered Selection Count

Select k=1 objects without order, replacement, or repetition from n=5 distinct objects. The empty selection counts once. Find C(5,1).

View answer and explanation

5

Count the k-element subsets exactly to obtain 5; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

36. Exact Unordered Selection Count

Select k=2 objects without order, replacement, or repetition from n=5 distinct objects. The empty selection counts once. Find C(5,2).

View answer and explanation

10

Count the k-element subsets exactly to obtain 10; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

37. Exact Unordered Selection Count

Select k=5 objects without order, replacement, or repetition from n=5 distinct objects. The empty selection counts once. Find C(5,5).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

38. Exact Unordered Selection Count

Select k=1 objects without order, replacement, or repetition from n=6 distinct objects. The empty selection counts once. Find C(6,1).

View answer and explanation

6

Count the k-element subsets exactly to obtain 6; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

39. Exact Unordered Selection Count

Select k=3 objects without order, replacement, or repetition from n=6 distinct objects. The empty selection counts once. Find C(6,3).

View answer and explanation

20

Count the k-element subsets exactly to obtain 20; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

40. Exact Unordered Selection Count

Select k=6 objects without order, replacement, or repetition from n=6 distinct objects. The empty selection counts once. Find C(6,6).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

41. Exact Unordered Selection Count

Select k=2 objects without order, replacement, or repetition from n=7 distinct objects. The empty selection counts once. Find C(7,2).

View answer and explanation

21

Count the k-element subsets exactly to obtain 21; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

42. Exact Unordered Selection Count

Select k=4 objects without order, replacement, or repetition from n=7 distinct objects. The empty selection counts once. Find C(7,4).

View answer and explanation

35

Count the k-element subsets exactly to obtain 35; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

43. Exact Unordered Selection Count

Select k=7 objects without order, replacement, or repetition from n=7 distinct objects. The empty selection counts once. Find C(7,7).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

44. Exact Unordered Selection Count

Select k=0 objects without order, replacement, or repetition from n=8 distinct objects. The empty selection counts once. Find C(8,0).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

45. Exact Unordered Selection Count

Select k=3 objects without order, replacement, or repetition from n=8 distinct objects. The empty selection counts once. Find C(8,3).

View answer and explanation

56

Count the k-element subsets exactly to obtain 56; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

46. Exact Unordered Selection Count

Select k=8 objects without order, replacement, or repetition from n=8 distinct objects. The empty selection counts once. Find C(8,8).

View answer and explanation

1

Count the k-element subsets exactly to obtain 1; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

47. Exact Unordered Selection Count

Select k=1 objects without order, replacement, or repetition from n=9 distinct objects. The empty selection counts once. Find C(9,1).

View answer and explanation

9

Count the k-element subsets exactly to obtain 9; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

48. Exact Unordered Selection Count

Select k=4 objects without order, replacement, or repetition from n=9 distinct objects. The empty selection counts once. Find C(9,4).

View answer and explanation

126

Count the k-element subsets exactly to obtain 126; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

49. Exact Unordered Selection Count

Select k=5 objects without order, replacement, or repetition from n=10 distinct objects. The empty selection counts once. Find C(10,5).

View answer and explanation

252

Count the k-element subsets exactly to obtain 252; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

50. Exact Unordered Selection Count

Select k=6 objects without order, replacement, or repetition from n=12 distinct objects. The empty selection counts once. Find C(12,6).

View answer and explanation

924

Count the k-element subsets exactly to obtain 924; the empty subset is one valid selection.

Reviewed step-by-step derivation

Permutations and combinations · qf-combination-exact-count · candidate

51. Choosing a Selection Model

Select k=0 objects with order distinguished, without replacement or repetition, from n=0 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

52. Choosing a Selection Model

Select k=1 objects with order ignored, without replacement or repetition, from n=1 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

53. Choosing a Selection Model

Select k=0 objects with order distinguished, without replacement or repetition, from n=2 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

54. Choosing a Selection Model

Select k=2 objects with order ignored, without replacement or repetition, from n=2 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

55. Choosing a Selection Model

Select k=1 objects with order distinguished, without replacement or repetition, from n=3 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

56. Choosing a Selection Model

Select k=3 objects with order ignored, without replacement or repetition, from n=3 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

57. Choosing a Selection Model

Select k=2 objects with order distinguished, without replacement or repetition, from n=4 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

58. Choosing a Selection Model

Select k=4 objects with order ignored, without replacement or repetition, from n=4 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

59. Choosing a Selection Model

Select k=0 objects with order distinguished, without replacement or repetition, from n=5 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

60. Choosing a Selection Model

Select k=1 objects with order ignored, without replacement or repetition, from n=5 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

61. Choosing a Selection Model

Select k=2 objects with order distinguished, without replacement or repetition, from n=5 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

62. Choosing a Selection Model

Select k=5 objects with order ignored, without replacement or repetition, from n=5 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

63. Choosing a Selection Model

Select k=1 objects with order distinguished, without replacement or repetition, from n=6 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

64. Choosing a Selection Model

Select k=3 objects with order ignored, without replacement or repetition, from n=6 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

65. Choosing a Selection Model

Select k=6 objects with order distinguished, without replacement or repetition, from n=6 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

66. Choosing a Selection Model

Select k=2 objects with order ignored, without replacement or repetition, from n=7 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

67. Choosing a Selection Model

Select k=4 objects with order distinguished, without replacement or repetition, from n=7 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

68. Choosing a Selection Model

Select k=7 objects with order ignored, without replacement or repetition, from n=7 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

69. Choosing a Selection Model

Select k=0 objects with order distinguished, without replacement or repetition, from n=8 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

70. Choosing a Selection Model

Select k=3 objects with order ignored, without replacement or repetition, from n=8 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

71. Choosing a Selection Model

Select k=8 objects with order distinguished, without replacement or repetition, from n=8 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

72. Choosing a Selection Model

Select k=1 objects with order ignored, without replacement or repetition, from n=9 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

73. Choosing a Selection Model

Select k=4 objects with order distinguished, without replacement or repetition, from n=9 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

74. Choosing a Selection Model

Select k=5 objects with order ignored, without replacement or repetition, from n=10 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

combination

The objects are distinct and selection is without replacement. Because order is ignored, use the combination model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

75. Choosing a Selection Model

Select k=6 objects with order distinguished, without replacement or repetition, from n=12 distinct objects. Should the model be a permutation or a combination?

View answer and explanation

permutation

The objects are distinct and selection is without replacement. Because order is significant, use the permutation model.

Reviewed step-by-step derivation

Permutations and combinations · qf-selection-model-choice · candidate

76. Quotient of Permutation and Combination Counts

For selection of k=0 distinct objects without replacement from n=0, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

77. Quotient of Permutation and Combination Counts

For selection of k=1 distinct objects without replacement from n=1, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

78. Quotient of Permutation and Combination Counts

For selection of k=0 distinct objects without replacement from n=2, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

79. Quotient of Permutation and Combination Counts

For selection of k=2 distinct objects without replacement from n=2, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

2

Each k-element subset has k! orderings, so the quotient is 2; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

80. Quotient of Permutation and Combination Counts

For selection of k=1 distinct objects without replacement from n=3, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

81. Quotient of Permutation and Combination Counts

For selection of k=3 distinct objects without replacement from n=3, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

6

Each k-element subset has k! orderings, so the quotient is 6; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

82. Quotient of Permutation and Combination Counts

For selection of k=2 distinct objects without replacement from n=4, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

2

Each k-element subset has k! orderings, so the quotient is 2; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

83. Quotient of Permutation and Combination Counts

For selection of k=4 distinct objects without replacement from n=4, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

24

Each k-element subset has k! orderings, so the quotient is 24; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

84. Quotient of Permutation and Combination Counts

For selection of k=0 distinct objects without replacement from n=5, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

85. Quotient of Permutation and Combination Counts

For selection of k=1 distinct objects without replacement from n=5, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

86. Quotient of Permutation and Combination Counts

For selection of k=2 distinct objects without replacement from n=5, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

2

Each k-element subset has k! orderings, so the quotient is 2; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

87. Quotient of Permutation and Combination Counts

For selection of k=5 distinct objects without replacement from n=5, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

120

Each k-element subset has k! orderings, so the quotient is 120; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

88. Quotient of Permutation and Combination Counts

For selection of k=1 distinct objects without replacement from n=6, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

89. Quotient of Permutation and Combination Counts

For selection of k=3 distinct objects without replacement from n=6, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

6

Each k-element subset has k! orderings, so the quotient is 6; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

90. Quotient of Permutation and Combination Counts

For selection of k=6 distinct objects without replacement from n=6, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

720

Each k-element subset has k! orderings, so the quotient is 720; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

91. Quotient of Permutation and Combination Counts

For selection of k=2 distinct objects without replacement from n=7, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

2

Each k-element subset has k! orderings, so the quotient is 2; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

92. Quotient of Permutation and Combination Counts

For selection of k=4 distinct objects without replacement from n=7, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

24

Each k-element subset has k! orderings, so the quotient is 24; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

93. Quotient of Permutation and Combination Counts

For selection of k=7 distinct objects without replacement from n=7, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

5040

Each k-element subset has k! orderings, so the quotient is 5040; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

94. Quotient of Permutation and Combination Counts

For selection of k=0 distinct objects without replacement from n=8, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

95. Quotient of Permutation and Combination Counts

For selection of k=3 distinct objects without replacement from n=8, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

6

Each k-element subset has k! orderings, so the quotient is 6; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

96. Quotient of Permutation and Combination Counts

For selection of k=8 distinct objects without replacement from n=8, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

40320

Each k-element subset has k! orderings, so the quotient is 40320; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

97. Quotient of Permutation and Combination Counts

For selection of k=1 distinct objects without replacement from n=9, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

1

Each k-element subset has k! orderings, so the quotient is 1; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

98. Quotient of Permutation and Combination Counts

For selection of k=4 distinct objects without replacement from n=9, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

24

Each k-element subset has k! orderings, so the quotient is 24; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

99. Quotient of Permutation and Combination Counts

For selection of k=5 distinct objects without replacement from n=10, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

120

Each k-element subset has k! orderings, so the quotient is 120; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

100. Quotient of Permutation and Combination Counts

For selection of k=6 distinct objects without replacement from n=12, compute the exact integer quotient P(n,k)/C(n,k). The empty selection counts once.

View answer and explanation

720

Each k-element subset has k! orderings, so the quotient is 720; the empty subset also has one ordering.

Reviewed step-by-step derivation

Permutations and combinations · qf-permutation-combination-quotient · candidate

Canonical question JSONL · English JSONL · Validation report