An urn contains 5 white and 10 black balls. A fair die is rolled and that numberof balls are randomly chosen from the urn. What is the probability that all of theballs selected are white?
You have to look at each scenario separately and then add them all the probabilities that you get together.
P(1 thrown and 1 while all drawn) = 1/6 * 5/15
P(2 thrown and 2 while all drawn) = 1/6 * 5/15 * 4/14