Leslie has two cups containing different-colored marbles. The first cup contains 7 pink marbles and 3 blue marbles. The second cup contains 3 black marbles, 1 red marble, and 6 orange marbles. What is the probability that Leslie will randomly select a blue marble from the first cup and then randomly select an orange marble from the second cup?

First of all, Leslie will choose a marble from the first cup. And she must choose blue one and its probability is 3/10. Because there are 10 marbles and 3 of them is blue. After that she will choose a marble from the second one and it must be orange. All of them is 3+1+6 = 10 and we have 6 orange marbles. It's probability is 6/10 = 3/5. We must multiple 3/10 and 3/5 because there are different situations and they depend on each other. So you must multiple them and answer is 3/10 * 3/5 = 9/50.