Question

A bag has 4 yellow balls and 6 red balls only. One ball is chosen at random and not replaced. A second ball is then chosen at random. Find the probability that both balls are yellow.

A. 2/15

B. 4/25

C. 2/5

D. 11/15

Answer 1

P(the 1^st ball is yellow) $= \frac{4}{4+6} = \frac{4}{10} = \frac{2}{5}$

P(the 2^nd ball is yellow) $= \frac{3}{9} = \frac{1}{3}$

The required probability $= \frac{2}{5} \times \frac{1}{3} = \frac{2}{15}$

Answer: A. 2/15