Page 1
PROBABILITY ASSIGNMENT
1. A positive integer is chosen at random. The probability that sum of the digits of its square is 33 is :
(A) 1/11 (B) 1/33
(C) 2/33 (D) None of these
2. Two persons A and B appear in an interview for two vacancies. If the probability of their selection are 1/4 and 1/6
respectively, then probabilities that none of them is selected is :
(A) 1/24 (B) 5/12
(C) 5/8 (D) 19/12
3. A bag contains 5 brown and 4 white socks. A man pulls out two socks. The probability that they are in the same
colour is :
(A) 5/108 (B) 1/6
(C) 5/18 (D) 4/9
4. Tickets are numbered 1 to 100. They are well–shuffled and a ticket is drawn at random. Probability that the drawn
ticket has a number 5 or a multiple of 5 is :
(A) 1/10 (B) 1/5
(C) 1/25 (D) 1/2
5. Out of 13 applicants for a job, there are 5 women and 8 men. It is desired to select 2 persons for the job.
The probability that at least one of the selected persons will be woman is :
(A) 25/39 (B) 14/39
(C) 5/13 (D) 10/13
6. From a well shuffled pack of playing cards, two cards are drawn one by one with replacement. The probability that
both are aces is :
(A) 2/13 (B) 1/51
(C) 1/221 (D) None of these
7. Three coins are tossed together. The probability of atleast two heads is :
(A) 1/8 (B) 3/8
(C) 1/2 (D) 1/4
8. Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is
(A) 1/18 (B) 1/12
(C) 1/9 (D) none of these
9. The probabilities of solving a problem by three students A, B, C are 1/2, 1/3, 1/4 respectively. The probability that
the problem will be solved is
(A) 1/4 (B) 1/2
(C) 3/4 (D) 1/3
10. The probability that a leap year selected at random contains 53 Sundays is
(A) 7/366 (B) 26/183
(C) 1/7 (D) 2/7
GIITJEE CHANDIGARH LIMITED SCO 382, Sector 37–D, Chandigarh – 160 036 Ph: 3290959 P – 1
Page 2
PROBABILITY ASSIGNMENT
1. A positive integer is chosen at random. The probability that sum of the digits of its square is 33 is :
(A) 1/11 (B) 1/33
(C) 2/33 (D) None of these
2. Two persons A and B appear in an interview for two vacancies. If the probability of their selection are 1/4 and 1/6
respectively, then probabilities that none of them is selected is :
(A) 1/24 (B) 5/12
(C) 5/8 (D) 19/12
3. A bag contains 5 brown and 4 white socks. A man pulls out two socks. The probability that they are in the same
colour is :
(A) 5/108 (B) 1/6
(C) 5/18 (D) 4/9
4. Tickets are numbered 1 to 100. They are well–shuffled and a ticket is drawn at random. Probability that the drawn
ticket has a number 5 or a multiple of 5 is :
(A) 1/10 (B) 1/5
(C) 1/25 (D) 1/2
5. Out of 13 applicants for a job, there are 5 women and 8 men. It is desired to select 2 persons for the job.
The probability that at least one of the selected persons will be woman is :
(A) 25/39 (B) 14/39
(C) 5/13 (D) 10/13
6. From a well shuffled pack of playing cards, two cards are drawn one by one with replacement. The probability that
both are aces is :
(A) 2/13 (B) 1/51
(C) 1/221 (D) None of these
7. Three coins are tossed together. The probability of atleast two heads is :
(A) 1/8 (B) 3/8
(C) 1/2 (D) 1/4
8. Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is
(A) 1/18 (B) 1/12
(C) 1/9 (D) none of these
9. The probabilities of solving a problem by three students A, B, C are 1/2, 1/3, 1/4 respectively. The probability that
the problem will be solved is
(A) 1/4 (B) 1/2
(C) 3/4 (D) 1/3
10. The probability that a leap year selected at random contains 53 Sundays is
(A) 7/366 (B) 26/183
(C) 1/7 (D) 2/7
GIITJEE CHANDIGARH LIMITED SCO 382, Sector 37–D, Chandigarh – 160 036 Ph: 3290959 P – 1
11. A bag contains 3 red, 4 white and 5 blue balls. All balls are different. Two balls are drawn at random.
The probability that they are of different colour is
(A) 47/66 (B) 10/33
(C) 5/22 (D) none of these
12. Three identical dice are rolled. The probability that the same number will appear on each of them is
(A) 1/6 (B) 1/18
(C) 1/36 (D) none of these
13. The probability that a man aged 50 years will die in a year is p. The probability that out of n men A
1
, A
2
, …., A
n
each aged 50 years, A
1
will die and be first to die is
(A) 1 – (1 – p)
n
(B) [1 – (1 – p)
n
] / n
2
(C) [1 – (1 – p)
n
] / n (D) none of these
14. A bag contains 3 white and 4 red balls. Another bag contains 5 white and 7 red balls. A ball is taken out of the first
bag and put in to the second. A ball is then taken out of the second bag. The probability that it is a red ball is
(A) 1/3 (B) 53/91
(C) 32/91 (D) none of these
15. A bag contains 10 mangoes out of which 4 are rotten, two mangoes are taken out together. If one of them is
found to be good, the probability that other is also good is
(A) 1/3 (B) 8/15
(C) 5/13 (D) 2/3
16. A card is drawn at random from a pack of 100 cards numbered 1 to 100. The probability of drawing a number
which is a square is
(A) 1/5 (B) 2/5
(C) 1/10 (D) none of these
17. The probability of India winning a test match against West Indies is 1/2. Assuming independence from match to
match the probability that in a 5 match series India's second win occurs at the third test is
(A) 1/8 (B) 1/4
(C) 1/2 (D) 2/3
18. The probability that at least one of the events A and B occurs is 0.7 and they occur simultaneously with probability
0.2. Then P( A ) + P( B ) =
(A) 1.8 (B) 0.6
(C) 1.1 (D) 1.4
19. Both A and B throw a dice. The chance that B throws a number higher than that thrown by A is
(A) 1/2 (B) 21/36
(C) 15/36 (D) none of these
20. The probability that a man can hit a target is 3/4. He tries 5 times. The probability that he will hit the target at least
three times is
(A) 291/364 (B) 371/464
(C) 471/502 (D) 459/512
GIITJEE CHANDIGARH LIMITED SCO 382, Sector 37–D, Chandigarh – 160 036 Ph: 3290959 P – 2
Page 3
PROBABILITY ASSIGNMENT
1. A positive integer is chosen at random. The probability that sum of the digits of its square is 33 is :
(A) 1/11 (B) 1/33
(C) 2/33 (D) None of these
2. Two persons A and B appear in an interview for two vacancies. If the probability of their selection are 1/4 and 1/6
respectively, then probabilities that none of them is selected is :
(A) 1/24 (B) 5/12
(C) 5/8 (D) 19/12
3. A bag contains 5 brown and 4 white socks. A man pulls out two socks. The probability that they are in the same
colour is :
(A) 5/108 (B) 1/6
(C) 5/18 (D) 4/9
4. Tickets are numbered 1 to 100. They are well–shuffled and a ticket is drawn at random. Probability that the drawn
ticket has a number 5 or a multiple of 5 is :
(A) 1/10 (B) 1/5
(C) 1/25 (D) 1/2
5. Out of 13 applicants for a job, there are 5 women and 8 men. It is desired to select 2 persons for the job.
The probability that at least one of the selected persons will be woman is :
(A) 25/39 (B) 14/39
(C) 5/13 (D) 10/13
6. From a well shuffled pack of playing cards, two cards are drawn one by one with replacement. The probability that
both are aces is :
(A) 2/13 (B) 1/51
(C) 1/221 (D) None of these
7. Three coins are tossed together. The probability of atleast two heads is :
(A) 1/8 (B) 3/8
(C) 1/2 (D) 1/4
8. Two dice are thrown simultaneously. The probability of obtaining a total score of 5 is
(A) 1/18 (B) 1/12
(C) 1/9 (D) none of these
9. The probabilities of solving a problem by three students A, B, C are 1/2, 1/3, 1/4 respectively. The probability that
the problem will be solved is
(A) 1/4 (B) 1/2
(C) 3/4 (D) 1/3
10. The probability that a leap year selected at random contains 53 Sundays is
(A) 7/366 (B) 26/183
(C) 1/7 (D) 2/7
GIITJEE CHANDIGARH LIMITED SCO 382, Sector 37–D, Chandigarh – 160 036 Ph: 3290959 P – 1
11. A bag contains 3 red, 4 white and 5 blue balls. All balls are different. Two balls are drawn at random.
The probability that they are of different colour is
(A) 47/66 (B) 10/33
(C) 5/22 (D) none of these
12. Three identical dice are rolled. The probability that the same number will appear on each of them is
(A) 1/6 (B) 1/18
(C) 1/36 (D) none of these
13. The probability that a man aged 50 years will die in a year is p. The probability that out of n men A
1
, A
2
, …., A
n
each aged 50 years, A
1
will die and be first to die is
(A) 1 – (1 – p)
n
(B) [1 – (1 – p)
n
] / n
2
(C) [1 – (1 – p)
n
] / n (D) none of these
14. A bag contains 3 white and 4 red balls. Another bag contains 5 white and 7 red balls. A ball is taken out of the first
bag and put in to the second. A ball is then taken out of the second bag. The probability that it is a red ball is
(A) 1/3 (B) 53/91
(C) 32/91 (D) none of these
15. A bag contains 10 mangoes out of which 4 are rotten, two mangoes are taken out together. If one of them is
found to be good, the probability that other is also good is
(A) 1/3 (B) 8/15
(C) 5/13 (D) 2/3
16. A card is drawn at random from a pack of 100 cards numbered 1 to 100. The probability of drawing a number
which is a square is
(A) 1/5 (B) 2/5
(C) 1/10 (D) none of these
17. The probability of India winning a test match against West Indies is 1/2. Assuming independence from match to
match the probability that in a 5 match series India's second win occurs at the third test is
(A) 1/8 (B) 1/4
(C) 1/2 (D) 2/3
18. The probability that at least one of the events A and B occurs is 0.7 and they occur simultaneously with probability
0.2. Then P( A ) + P( B ) =
(A) 1.8 (B) 0.6
(C) 1.1 (D) 1.4
19. Both A and B throw a dice. The chance that B throws a number higher than that thrown by A is
(A) 1/2 (B) 21/36
(C) 15/36 (D) none of these
20. The probability that a man can hit a target is 3/4. He tries 5 times. The probability that he will hit the target at least
three times is
(A) 291/364 (B) 371/464
(C) 471/502 (D) 459/512
GIITJEE CHANDIGARH LIMITED SCO 382, Sector 37–D, Chandigarh – 160 036 Ph: 3290959 P – 2
21. The probability that a person will hit a target in shooting practice is 0.3. If he shoots 10 times, the probability that
he hits the target is
(A) 1 (B) 1 – (0.7)
10
(C) (0.7)
10
(D) (0.3)
10
22. A and B are two independent events. The probability that both A and B occur is 1/6 and the probability that neither
of them occurs is 1/3. Then
(A) P (A) = 1/2, P (B) = 1/3 (B) P (A) = 1/2, P (B) = 1/6
(C) P (A) = 1/3, P (B) = 1/2 (D) none of these
23. In a class of 125 students 70 passed in Mathematics, 55 in Statistics and 30 in both. The probability that a student
selected at random from the class, has passed in only one subject is
(A) 13/25 (B) 3/25
(C) 17/25 (D) 8/25
24. A lot consists of 12 good pencils, 6 with minor defects and 2 with major defects. A pencil is chosen at random.
The probability that this pencil is not defective is
(A) 3/5 (B) 3/10
(C) 4/5 (D) 1/2
25. 3 mangoes and 3 apples are in a box. If 2 fruits are chosen at random, the probability that one is a mango and the
other is an apple is
(A) 3/5 (B) 5/6
(C) 1/36 (D) none of these
26. A father has 3 children with at least one boy. The probability that he has 2 boys and one girl is
(A) 1/4 (B) 1/3
(C) 2/3 (D) none of these
27. Out of 13 applicants for a job, there are 5 women and 8 men. It is desired to select 2 persons for the job.
The probability that at least one of the selected persons will be a woman is
(A) 25/39 (B) 14/39
(C) 5/13 (D) 10/13
28. Two events A and B have probability 0.25 and 0.50. The probability that both occur simultaneously is 0.14.
The probability that neither A nor B occurs is
(A) 0.75 (B) 0.61
(C) 0.39 (D) none of these
29. If A and B are independent events and P (A ? B) = 9/10, P (B) = 4/10, then P (A) =
(A) 1/6 (B) 5/6
(C) 1/9 (D) none of these
30. A, B, C in order toss a coin. The first one to throw a head wins. Assuming the game continues indefinite their
respective chances of winning the game are
(A) 4/7, 2/7, 1/7 (B) 1/7, 4/7, 2/7
(C) 2/7, 4/7, 1/7 (D) none of these
GIITJEE CHANDIGARH LIMITED SCO 382, Sector 37–D, Chandigarh – 160 036 Ph: 3290959 P – 3
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