Counting, induction and discrete probability: basics of counting, pigeonhole principle, permutations and combinations, inclusion–exclusion principle, mathematical induction, probability, Bayes' theorem. - One Line Questions

1. Using the Inclusion-Exclusion Principle for two sets A and B, what is the formula for |A U B|? |A| + |B| - |A ∩ B|
2. What is the probability of an event that is certain to occur? 1
3. What is the probability of an event that is impossible to occur? 0
4. What is the value of C(n, n)? 1
5. What is the value of P(n, 1)? n
6. A survey of 100 people found that 70 like coffee and 80 like tea. If 60 people like both, how many like neither? 10
7. If P(A) = 0.6, P(B) = 0.5, P(A U B) = 0.8, what is P(A ∩ B)? 0.3
8. If P(A) = 0.6 and P(B) = 0.7 and P(A and B) = 0.4, what is P(A or B)? 0.9
9. If P(A) = 0.5, P(B) = 0.4, and P(A|B) = 0.8, what is P(A and B)? 0.32
10. Consider the statement: 1 + 2 + ... + n = n(n+1)/2. If the inductive step assumes P(k) is true, what needs to be proven? 1 + 2 + ... + (k+1) = (k+1)(k+2)/2
11. What is the probability that a randomly selected integer from 1 to 10 is divisible by 3? 3/10
12. What is the probability of drawing an ace from a standard deck of 52 cards? 1/13
13. What is the probability of getting at least one head when flipping a fair coin 4 times? 15/16
14. What is the probability of rolling a sum of 7 with two standard six-sided dice? 6/36
15. What is the probability of drawing a spade or a heart from a standard deck of 52 cards? 26/52
16. What is the probability of getting exactly 2 heads in 3 coin flips? 3/8
17. Consider a set of 5 distinct books. How many ways can you arrange 3 of them on a shelf? 60
18. In how many ways can a committee of 3 people be chosen from a group of 10 people? 120
19. What is the minimum number of students in a class to guarantee that at least two students receive the same score on a test graded from 0 to 100? 102
20. How many ways can the letters of the word 'BOOK' be arranged? 12
21. How many ways can the letters of the word 'APPLE' be arranged? 60
22. How many non-negative integer solutions are there to the equation x1 + x2 + x3 = 10? 120
23. In a class of 30 students, 15 like Math and 20 like Science. If 5 students like both, how many students like either Math or Science? 25
24. How many different outcomes are possible when flipping a coin 3 times? 8
25. How many permutations are there of the set {a, b, c}? 6
26. In a group of 20 people, 12 play cricket and 15 play football. If each person plays at least one game, how many play both? 5
27. Suppose a bag contains 5 red balls and 3 blue balls. If you draw one ball at random, what is the probability it is red? 5/8
28. How many distinct permutations are there of the letters in the word 'MISSISSIPPI'? 11! / (4! * 4! * 2! * 1!)
29. What is the value of 5! (5 factorial)? 120
30. In how many ways can 5 people be seated in a row? 120
31. What is the total number of possible outcomes when rolling two distinct dice? 36
32. If you have 3 shirts and 4 pants, how many different outfits can you create? 12
33. How many ways can you choose a team of 4 players from a group of 7? 28
34. What are the two steps involved in a proof by mathematical induction? Base case and Inductive step
35. What is the principle of mathematical induction used for? Proving statements about natural numbers
36. In probability, what is the set of all possible outcomes of an experiment called? Sample Space
37. In Bayes' Theorem, P(A|B) = P(B|A) * P(A) / P(B), what is P(A) called? Prior Probability
38. If a task can be performed in m ways, and after it is performed, a second task can be performed in n ways, then the two tasks can be performed in sequence in how many ways? m * n
39. If a task can be performed in m ways and a second task can be performed in n ways, and these tasks cannot be performed at the same time, then the task can be performed in how many ways? m + n
40. What is the formula for the number of permutations of n objects where there are n1 identical objects of type 1, n2 identical objects of type 2, ..., nk identical objects of type k? n! / (n1! * n2! * ... * nk!)
41. What is the number of permutations of n distinct objects taken r at a time, denoted as P(n, r)? n! / (n-r)!
42. What is the number of combinations of n distinct objects taken r at a time, denoted as C(n, r)? n! / (r! * (n-r)!)
43. What is the formula for conditional probability P(A|B)? P(A and B) / P(B)
44. If events A and B are independent, what is P(A and B)? P(A) * P(B)
45. What is the fundamental principle that states if n items are put into m containers, with n > m, then at least one container must contain more than one item? Pigeonhole Principle
46. Which principle is used to count the number of elements in the union of multiple sets? Inclusion-Exclusion Principle
47. In the context of the Pigeonhole Principle, what are the 'pigeons' and 'pigeonholes' in the statement: 'If you have 5 pigeons and 4 pigeonholes, at least one pigeonhole must contain more than one pigeon'? Pigeons are the items, pigeonholes are the containers.
48. If you are proving a statement P(n) for all integers n >= 1, what is the first step in mathematical induction? Prove P(1) is true.
49. What is the base case in a proof by induction for the statement P(n)? Proving P(1) is true
50. What does Bayes' Theorem describe? The probability of an event given prior knowledge of related events