Box A contains 4 red and 6 blue balls. Box B contains 5 red and 10 blue balls. A box is selected at random and a ball is drawn. Find the probability that the ball is blue, given that it came from Box B.

2 answers

There's 1/2 chance that you'll choose Box B, and there's 10/15 chance that it'll be a blue ball. To find the probability, multiply the two numbers.
That is what I got on my quiz--answer he told me was 10/19??