3 +2 = 5 total marbles in bag a. 3 are white, so they have a 3/5 probability of picking white in bag a.
6+3 = 9 total marbles in bag b. 6 are white, so they have a 6/9, which reduces to a 2/3 probability of getting white in bag b.
Probability of getting white in both: 3/5 x 2/3 = 6/15 reduces to 2/5 total probability.
