a box contains 5 red b***s, 7 green b***s, and 6 yellow b***s. In how many ways can 6 b***s be chosen if there should be 2 b***s of each color?
We want to chose 2 of the 5 red, 2 of the 7 green and 2 of the 6 yellow......so we have :
C(5,2) * C(7,2) * C (6,2) = 3150 ways
