Quantitative Aptitude

General Questions

Quantitative Aptitude Exercise Mode

General Questions

Practice and master this topic with our carefully crafted questions.

10 Questions
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Question 1
Three unbiased coins are tossed. What is the probability of getting at most two heads?

A
3/4
B
1/4
C
3/8
D
7/8
Correct Answer: Option D

Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH}

Let E = event of getting at most two heads.

Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}.

P(E) = n(E) = 7 .
n(S) 8

Question 2
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?

A
1/3
B
3/4
C
7/19
D
8/21
E
9/21
Correct Answer: Option A

Total number of balls = (8 + 7 + 6) = 21.

Let E = event that the ball drawn is neither red nor green
= event that the ball drawn is blue.

n(E) = 7.

P(E) = n(E) = 7 = 1 .
n(S) 21 3

Question 3
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?

A
1/2
B
2/5
C
8/15
D
9/20
Correct Answer: Option D

Here, S = {1, 2, 3, 4, ...., 19, 20}.

Let E = event of getting a multiple of 3 or 5 = {3, 6 , 9, 12, 15, 18, 5, 10, 20}.

P(E) = n(E) = 9 .
n(S) 20

Question 4
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?

A
3/4
B
4/7
C
1/8
D
3/7
Correct Answer: Option B

Let number of balls = (6 + 8) = 14.

Number of white balls = 8.

P (drawing a white ball) = 8 = 4 .
14 7

Question 5
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:

A
1/22
B
3/22
C
2/91
D
2/77
Correct Answer: Option C

Let S be the sample space.

Then, n(S) = number of ways of drawing 3 balls out of 15
= 15C3
= (15 x 14 x 13)
(3 x 2 x 1)
= 455.

Let E = event of getting all the 3 red balls.

n(E) = 5C3 = 5C2 = (5 x 4) = 10.
(2 x 1)

P(E) = n(E) = 10 = 2 .
n(S) 455 91

Question 6
A card is drawn from a pack of 52 cards. The probability of getting a queen of club or a king of heart is:

A
1/13
B
2/13
C
1/26
D
1/52
Correct Answer: Option C

Here, n(S) = 52.

Let E = event of getting a queen of club or a king of heart.

Then, n(E) = 2.

P(E) = n(E) = 2 = 1 .
n(S) 52 26

Question 7
One card is drawn at random from a pack of 52 cards. What is the probability that the card drawn is a face card (Jack, Queen and King only)?

A
1/13
B
3/13
C
1/4
D
9/52
Correct Answer: Option B

Clearly, there are 52 cards, out of which there are 12 face cards.

P (getting a face card) = 12 = 3 .
52 13

Question 8
Two cards are drawn together from a pack of 52 cards. The probability that one is a spade and one is a heart, is:

A
3/20
B
29/34
C
47/100
D
13/102
Correct Answer: Option D

Let S be the sample space.

Then, n(S) = 52C2 = (52 x 51) = 1326.
(2 x 1)

Let E = event of getting 1 spade and 1 heart.

n(E) = number of ways of choosing 1 spade out of 13 and 1 heart out of 13
= (13C1 x 13C1)
= (13 x 13)
= 169.

P(E) = n(E) = 169 = 13 .
n(S) 1326 102

Question 9
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?

A
10/21
B
11/21
C
2/7
D
5/7
Correct Answer: Option A

Total number of balls = (2 + 3 + 2) = 7.

Let S be the sample space.

Then, n(S) = Number of ways of drawing 2 balls out of 7
= 7C2 `
= (7 x 6)
(2 x 1)
= 21.

Let E = Event of drawing 2 balls, none of which is blue.

n(E) = Number of ways of drawing 2 balls out of (2 + 3) balls.
= 5C2
= (5 x 4)
(2 x 1)
= 10.

P(E) = n(E) = 10 .
n(S) 21

Question 10
What is the probability of getting a sum 9 from two throws of a dice?

A
1/6
B
1/8
C
1/9
D
1/12
Correct Answer: Option C

In two throws of a dice, n(S) = (6 x 6) = 36.

Let E = event of getting a sum ={(3, 6), (4, 5), (5, 4), (6, 3)}.

P(E) = n(E) = 4 = 1 .
n(S) 36 9

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