Question

A box contains 6 red and 4 white balls. If 3 balls are drawn at random, the probability of getting 2 white balls without replacement is …

(a) 1/20

(b) 18/25

(c) 4/25

(d) 3/10

Answer 1

(d) 3/10

Total number of balls = 10 

Number of ways of choosing 3 balls from 10 balls 

= 10C₃

Number of ways of choosing 2 white balls from 4 white balls = 4C₃ 

Number of ways of choosing 1 red ball from 6 red balls = 6C₁

Probability of getting 2 white balls and 1 red ball