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
