Question

a bag contains 80 red balls ,30 white balls and few blue balls find the number of blue balls in the bag if the probability of a getting a white balls is 1/5​

Answer 1

Let the number of blue balls be x

Total no of balls=80+30+x=110+x

Sample space is of drawing one ball from 110+x balls.it can be done in 110+xC1 ways

110+xC1=110+x(nC1=n)

The event is that the ball drawn is white. This can be done in 30C1 ways

30C1= 30(nCi=n)

Probability of drawing on white ball=30/(110+x)

Given probability=1/5

30/(110+x)=1/5

30*5=110+x

150=110+x

x=150–110

x=40

Number of blue balls is 40

Answer 2

Answer:

let rhe no. of blue balls be x

Step-by-step explanation:

probability of getting a white ball = no. of white balls / total no. of balls

1/5 = 30/ 80+30+ x

1/5 = 30/ 110 + x

110 + x = 30 × 5

x = 150 - 110

x = 40

the number of blue balls is 40