A bag contains 5 red, 3 green, and 6 marbles. If a child grabs three marbles, find P(at least 2 blue marbles).

Answer 1

I assume you mean 6 blue marbles, making 14 in all.

Looking just at the blues,
P(0) = 8/14 * 7/13 * 6/12 = 2/13
P(1) = 6/14 * 8/13 * 7/12 = 2/13
So, P(>=2) = 1-(2/13 + 2/13) = 9/13