Question

A box contains 8 white and 12 yellow balls. Two balls are chosen at random. What is the probability that both are of same colour?

Answer 1

white balls =8
yellow balls=12
probability of getting both white balls = 2/8=1/4
probability of getting both yellow balls=2/12=1/6

Answer 2

white balls = 8
yellow balls=8

probability of getting white balls= 8/12 + 8
= 8/20 = 2/5
probability of getting yellow balls= 12/ 12 + 8
= 12/20 = 3/5