Question

Two urns contain white balls and yellow balls. The first urn contains 5 white balls and 8 yellow balls and the second urn contains 9 white balls and 2 yellow balls. A ball is drawn at random from each urn. What is the probability that both balls are white?

Answer 1

About 31.5% when rounded. 

This is because you have to start with the probability of each urn. The first urn has 13 total balls (5 white and 8 yellow). Since 5 of them are white, the odds of pulling a white ball are 5/13. Then find the same for the second urn (9 white and 2 yellow). Therefore there are 11 total balls and 9/11 chance of getting a white one. After finding both, multiply them together to get the answer.

$\frac{5}{13}$*$\frac{9}{11}$= $\frac{45}{143}$= 31.5%