Question

A jar contains 18 balls. 3 blue balls are removed from the jar and not replaced. Now the probability of getting a blue ball is 1/5 then how many blue balls jar contains initially?

Answer 1

let blue balls = x

blue balls left after removing 3 = x-3

now total balls left in jar = 18-3 = 15

according to question

x-3/15=1/15

after cross multiplication

5x-15= 15

5x=30

x = 30/5

x=6

now there are total 6 blue balls left.

hope it will help you...