## Probability Worksheet Solution3

In this page probability worksheet solution3 we are going to see solution of some practice questions of the probability worksheet.

Question 7

Three coins are tossed simultaneously. Find the probability of getting

(ii) exactly two tails

Solution:

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

n(S) = 8

(i)Let A be event of getting at least one head

A = { HHH, HHT, HTH, THH, HHT, THT, TTH}

n(A) = 7

Probability of getting at least one head, P(A) = n (A)/n(S)

P(A) = 7/8

(ii)Let B be event of getting exactly two tails

B = {HTT, THT, TTH}

n(B) = 3

Probability of getting exactly two tails, P(B) = n (B)/n(S)

P(B) = 3/8

(i) Probability of getting at least one head, P(A) = 7/8

(ii) Probability of getting exactly two tails, P(B) = 3/8

Question 8

A bag contains 6 white balls numbered from 1 to 6 and 4 red balls numbered from 7 to 10. A ball is drawn at random. Find the probability of getting

(i) an even numbered ball

(ii)  a white ball

Solution:

Total number of balls =10

n(S) = 10

(i) Let A be the event of getting an even numbered ball

A = {2,4,6,8,10}

n(A) = 5

Probability of getting an even numbered ball, P(A) =  n(A)/n(S)

= 5/10

P(A) = 1/2

(ii) Let B be the event of getting a white ball

There are 6 white balls

n(B) = 6

Probability of getting white ball, P(B) =  n(B)/n(S)

= 6/10

P(B) = 3/5

(i) Probability of getting an even numbered ball, P(A) = 1/2

(ii) Probability of getting white ball, P(B) = 3/5

Question 9

A number is selected at random from integers 1 to 100. Find the probability that it is

(i) a perfect square

(ii) not a perfect square

Solution:

Sample space = {1,2,3,4,5,…………………….100}

(i)  Let A be the event of getting a perfect square

A={1,4,9,16,25,36,49,64,81,100}

n(A) = 10

Probability of getting a perfect square number, P(A) = n(A)/n(S)

= 10/100

= 1/10

(ii)Let B be the event of getting not a perfect square

Probability of getting a perfect square number, P(B) = 1 - P(A)

= 1-[1/10]

= (10-1)/10

P(B) = 9/10

(i) Probability of getting a perfect square number, P(A) = 1/10

(ii) Probability of getting a perfect square number, P(B) = 9/10 probability worksheet solution3 probability worksheet solution3 