A bag contains 12 white balls and ‘x’ blue balls. The probability of picking a white ball at random from the bag is 3/5

A bag contains 12 white balls and ‘x’ blue balls. The probability of picking a white ball at random from the bag is 3/5. Find the sum of the number of white and blue balls in the bag.

a)            25

b)            30

c)            40

d)            20

e)            None of these

Sol:

Probability of picking a white ball = number of

white balls/total number of balls

3/5 = 12/(x+12)

3x + 36 = 60

x = 24/3

x = 8

Total number of balls = 12+8 = 20