A bag contains 1 red, 7 black and two yellow marbles. What is the probability of selecting 1 yellow marble, not replacing it then selecting another yellow marble?

Question

How do you solve this?

Answer 1

there are initially 2 yellows out of a total of 10 marbles.

chance of yellow on 1st draw: 2/10

with that yellow gone, there is now only 1 yellow out of 9 total, so the chance of a yellow on the 2nd draw is 1/9

So, the total probability is 2/10 * 1/9