Probability

What will be the probability of getting odd numbers if a dice is thrown?

• 0.2

• 0.5

• 1.5

• 3

Answer explanation

S = {1,2,3,4,5,6}

A = {1,3,5}

P{A} = n(A)/n(S)

= 3/6

= 1/2

Out of 300 students in a school, 95 play cricket only, 120 play football only, 80 play volleyball only and 5 play no games. If one student is chosen at random, find the probability that

(i) he plays volleyball

• 4/15

• 2/5

• 1/3

• 1/2

Out of 300 students in a school, 95 play cricket only, 120 play football only, 80 play volleyball only and 5 play no games. If one student is chosen at random, find the probability that

(ii) he plays either cricket or volleyball

• 4/15

• 2/5

• 7/12

• 1/5

Out of 300 students in a school, 95 play cricket only, 120 play football only, 80 play volleyball only and 5 play no games. If one student is chosen at random, find the probability that

(iii) he plays neither football nor volleyball.

• 1/3

• 2/5

• 4/15

• 2/5

The probability of getting two tails when two coins are tossed is

• 1/6

• 1/2

• 1/3

• 1/4

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?

• 1/2

• 2/5

• 8/15

• 9/20

Answer explanation

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)/n(S) = 9/20.

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

• 11/21

• 2/7

• 5/7

Answer explanation

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?

• 7/19

• 3/4

• 1/3

• 8/21

• 9/21

Answer explanation

A box contains 4 blue, 3 red, 2black balls. If two balls are selected at random from the box, what is the probability that one is blue and one is red ball?

• 1/6

• 1/3

• 2/9

• 1/9

• 2/3

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

• 1/13

• 2/13

• 1/26

• 1/52

Answer explanation

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)/n(S) = 2/52 = 1/26.