Probablity ( Quantitative Aptitude ) Practice Questions

1.     In a throw of a coin, find the probability of getting a head.(1/2)
2.     Two unbiased coin are tossed .what is the probability of getting at most one head?(3/4)
3.     An unbiased die is tossed .find the probability of getting a multiple of 3?(1/3)
4.     In a simultaneous  throw of pair of dice .find the probability of getting the total more than 7?(5/12)
5.     A bag contains 6 white and 4 black balls .2 balls are drawn at random. Find the probability that they are of same colour.(7/15)
6.     Two dice are thrown together .What is the probability that the sum of the number on the two faces is divided by 4 or 6. (7/18)
7.     Two cards are drawn at random from a pack of 52 cards. What is the probability that either both are black or both are queen? (55/221)
EXERCISE
1.     In a simultaneous throw of two coins, the probability of getting at least one head is:(3/4)
2.     Three unbiased coins are tossed. What is the probability of getting at least 2 heads?(1/2)
3.     Three unbiased coins are tossed. What is the probability of getting at most two heads?(7/8)
4.     In a single throw of a die, what is the probability of getting a number greater than 4?(1/3)
5.     In a simultaneous throw of two dice, what is the probability of getting a total of 7?(1/6)
6.     What is the probability of getting a sum 9 from two throws of a dice?(1/9)
7.     In a simultaneous throw of two dice, what is the probability of getting a doublet?(1/6)
8.     In a simultaneous throw of two dice, what is the probability of getting a total of 10 or 11 ?(5/36)
9.     Two dice are thrown simultaneously. What is the probability of getting two numbers whose product is even?(3/4)
10.                        Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn bears a number which is a multiple of 3?(3/10)
11.                        Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?(9/20)
12.                        In a lottery, there are 10 prizes and 25 blanks. A lottery is drawn at random. What is the probability of getting a prize?(2/7)
13.                        One card is drawn at random from a pack of 52 cards. What is the probability that the card drawn is a face card?(4/13)
14.                        A card is drawn from a pack of 52 cards. The probability of getting a queen of club or a king of heart is :(1/26)
15.                        One card is drawn from a pack of 52 cards. What is the probability that the card drawn is either a red card or a king?(7/13)
16.                        From a pack of 52 cards, one card is drawn at random. What is the probability that the card drawn is a ten or a spade?(4/13)
17. The probability that a card drawn from a pack of 52 cards will be a diamond or a king, is(4/13)
18.                        From a pack of 52 cards, two cards are drawn together at random. What is the probability of both the cards being kings?(1/221)
19.                        Two cards are drawn together from a pack of 52 cards. The probability that one is a spade and one is a heart, is (29/34)
20.                        Two cards are drawn from a pack of 52 cards. The probability that either both are red or both are kings, is :(55/221)
21.                        A bag contains 6 black and 8 white balls. One ball is drawn at random. What is the probability that the ball drawn is white?(4/7)
22.                        A box contains 5 green, 4 yellow and 3 white marbles. Three marbles are drawn at random. What is the probability that they are not of the same colour?(41/44)
23.                        A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is :(2/91)
24.                        A bag contains 6 white and 4 red balls. Three balls are drawn at random. What is the probability that one ball is red and the other two are white?(1/2)
25.                        A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?(10/21)
26.                        In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?(8/21)
27.                        A box contains 10 black and 10 white balls. The probability of drawing two balls of the same colour, is :(9/19)
28.                        A box contains 4 red balls, 5 green balls and 6 white balls. A ball is drawn at random from the box. What is the probability that the ball drawn is either red or green?(3/5)
29.                        In,a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is :(21/46)
30.                        Four persons are chosen at random from a group of 3 men, 2 women and 4 children The chance that exactly 2 of them are children, is :(10/21)
31.                        A box contains 20 electric bulbs, out of which 4 are defective. Two bulbs are chosen at random from this box. The probability that at least one of these is defective, is :(7/19)
32.                        In a class, 30% of the students offered English, 20% offered Hindi and 10% offered both. If a student is selected at random, what is the probability that ha has offered English or Hindi?(2/5)
33.                        Two dice are tossed. The probability that the total score is a prime number is (5/12)
34.                        A speaks truth in 75% cases and B in 80% of the cases. In what percentage of cases are they likely to contradict each other, narrating the same incident? (35%)

35.                        A man and his wife appear in an interview for two vacancies in the same post. The probability of husband’s selection is (1 / 7) and the probability of wife’s selection is (1 / 5). What is the probability that only one of them is selected? (2/7)