Quantitative Aptitude

Probability

1,860 Questions
All Sample Space Setup 558 Permutation & Combination Counting 288 Multiplication Theorem (AND) 234 Addition Theorem (OR) 151 At Least One Probability 134 Complement Rule (P(Not A)) 130 Drawing Without Replacement 126 Conditional Probability 75 Bayes' Theorem 69 Drawing With Replacement 49 Success and Failure Rates 46

Probability Questions

Multiple choice

Quantity A Number of ways to select 2 balls at random from 30 balls Quantity B Number of ways to select 2 balls at random, one red and one white, when there are 15 red and 15 white balls

  1. Quantity A is greater.

  2. Quantity B is greater.

  3. The two quantities are equal.

  4. The relationship cannot be determined from the information given.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Quantity A: 30C2 = (30*29)/2 = 435. Quantity B: 15C1 * 15C1 = 15 * 15 = 225. Since 435 > 225, Quantity A is greater.

Multiple choice

Quantity A Quantity B Probability of getting sum between 1 and 6 (both inclusive) when two dice are rolled together. Probability of getting sum between 7 and 12 (both inclusive) when two dice are rolled together.

  1. Quantity A is greater.

  2. Quantity B is greater.

  3. The two quantities are equal.

  4. The relationship cannot be determined from the information given.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sum 1-6: (1,1), (1,2), (1,3), (1,4), (1,5), (2,1), (2,2), (2,3), (2,4), (3,1), (3,2), (3,3), (4,1), (4,2), (5,1). Total 15 outcomes. Sum 7-12: 21 outcomes. Since 21 > 15, Quantity B is greater.

Multiple choice

Directions: Compare Quantity A and Quantity B using additional information centered above the two quantities if such information is given. Select one of the four answer choices. Four cards are drawn from a pack of 52 playing cards. Quantity A Quantity B Probability of getting all the four cards of same suit. 44/4165

  1. Quantity A is greater than quantity B.

  2. Quantity B is greater than quantity A.

  3. Both the quantities are equal.

  4. The relationship between the quantities cannot be determined.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Probability of 4 cards of the same suit: Choose 1 suit (4 ways), then choose 4 cards from 13 (C(13,4)). Total ways = C(52,4). P = (4 * C(13,4)) / C(52,4) = (4 * 715) / 270725 = 2860 / 270725 = 44 / 4165. Both quantities are equal.

Multiple choice

Directions: Compare Quantity A and Quantity B, using additional information centered above the two quantities if such information is given. Select one of the four answer choices. If 2 dice are rolled, the probability of getting a sum 'x' is 1/36. Quantity A Quantity B x 2

  1. Quantity A is greater than quantity B.

  2. Quantity B is greater than quantity A.

  3. Both the quantities are equal.

  4. The relationship between the quantities cannot be determined.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The probability of a sum x from 2 dice depends on the value of x. Since x is not defined in the problem statement, we cannot determine the probability or compare it to 2.

Multiple choice

A bag contains coloured discs. Riya selects a disc at random, notes its colour, and then replaces it. She does this 500 times and her results are shown below: Blue Green Red Yellow White 8 85 200 115 92 Riya hands the bag to Peter, who is going to select one disc from the bag. Based on Riya's experiment, find the experimental probability that Peter selects a red disc.

  1. 0.4

  2. 0.6

  3. 0.2

  4. 0.14

  5. NA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Experimental probability = (Number of times event occurred) / (Total number of trials). Red occurred 200 times out of 500 trials. 200/500 = 2/5 = 0.4.