Probability
Ten quantitative aptitude questions, each marked as you answer.
-
Two fair dice are thrown together. What is the probability that the sum is at least 8?
Answer and working
Answer C
There are 36 equally likely outcomes and 15 of them qualify. Probability = 5⁄12.
-
Two fair dice are thrown together. What is the probability that the sum is at least 4?
Answer and working
Answer D
There are 36 equally likely outcomes and 33 of them qualify. Probability = 11⁄12.
-
A bag holds 6 red, 5 blue and 2 green balls. One ball is drawn at random. What is the probability that it is red?
Answer and working
Answer B
6 of the 13 balls are red. Probability = 6⁄13.
-
One card is drawn at random from a well-shuffled pack of 52. What is the probability that it is a face card?
Answer and working
Answer C
12 of the 52 cards qualify. Probability = 3⁄13.
-
Three fair coins are tossed. What is the probability of getting at least two heads?
Answer and working
Answer D
Of the 8 equally likely outcomes, 4 qualify. Probability = 1⁄2.
-
Two fair dice are thrown together. What is the probability that the sum is at least 10?
Answer and working
Answer B
There are 36 equally likely outcomes and 6 of them qualify. Probability = 1⁄6.
-
Three fair coins are tossed. What is the probability of getting all heads or all tails?
Answer and working
Answer C
Of the 8 equally likely outcomes, 2 qualify. Probability = 1⁄4.
-
Two fair dice are thrown together. What is the probability that both show the same number?
Answer and working
Answer C
There are 36 equally likely outcomes and 6 of them qualify. Probability = 1⁄6.
-
One card is drawn at random from a well-shuffled pack of 52. What is the probability that it is a spade or an ace?
Answer and working
Answer C
16 of the 52 cards qualify. Probability = 4⁄13.
-
Two fair dice are thrown together. What is the probability that the sum is at least 4?
Answer and working
Answer D
There are 36 equally likely outcomes and 33 of them qualify. Probability = 11⁄12.
More quantitative aptitude: Percentages, Profit, loss and discount, Simple interest, Compound interest, Ratio and proportion, Averages.