# Quantitative Aptitude: Probability Questions – Set 10

1. A bag contains 12 white and 18 black balls. Two balls are drawn in succession without replacement.
37/145
35/142
33/141
36/145
31/140
Option D
Required probability,
=(2/5)×(18/29)
=36/145

2. There are four hotels in a town. If 3 men check into the hotels in a day then what is the probability that each checks into a different hotel?
1/4
2/5
3/8
4/9
2/7
Option C
Required probability
=24/4^3
=3/8

3. A card is drawn from a pack of 52 cards. The card is drawn at random. What is the probability that it is neither a spade nor a Jack?
8/11
5/7
4/5
9/13
8/13
Option D
Probability of getting spade or a jack
=(13+3)/52
=4/13
So probability of getting neither spade nor a jack
=1−4/13
=9/13

4. A bag contains 5 red and 3 green balls. Another bag contains 4 red and 6 green balls. If one ball is drawn from each bag. Find the probability that one ball is red and one is green.
17/42
21/40
19/44
20/43
19/41
Option B
Required probability = 3/8+3/20 = 21/40

5. Two brother X and Y appeared for an exam. The probability of selection of X is 1/7 and that of B is 2/9. Find the probability that both of them are selected.
4/65
2/63
2/65
3/62
2/61
Option B
Probability =(1/7)*(2/9)
=2/63

6. Two brothers appeared for an exam. The probability of each of them getting selected is 1/4 and 1/6 respectively. Find the probability that only one of the two are selected.
1/7
1/5
1/4
1/2
1/3
Option E
Probability that only of the two are selected
= [(1/4)*(5/6)]+[(3/4)*(1/6)]= [5/24]+[3/24]= 8/24
= 1/3

7. A card is selected at random from a pack of cards. After replacing it, another draw is made. Find the probability that the first card is a spade and the second is a club.
1/18
1/16
1/17
1/13
1/15
Option B
P(drawing a spade) = 13/52 = 1/4
P(drawing a club) = 1/4
Probability = (1/4)*(1/4) = 1/16

8. A bag contains 2 red, 4 blue and 6 green balls. If one ball is drawn from the bag, what is the probability that it is red or green?
2/3
5/6
5/9
3/7
2/5
Option A
Required Probability = 8/12 = 2/3

9. Two friends appear for an interview. The probability of each of them getting selected is 1/5 and 1/6 respectively. Find the probability that both are selected.
1/35
1/33
1/30
1/31
1/29
Option C
P(both being selected)
= (1/5)*(1/6)
= 1/30

10. Three unbiased coins are tossed. What is the probability of getting at most two heads ?
6/7
3/5
8/9
7/8
4/5
Option D
Probability = 7/8