There are 5 blue chips, 4 red chips and 3 yellow chips in a bag. One chip is drawn from the bag. That chip is placed back into the bag, and a second chip is drawn. What is the probability that the two selected chips are of different colors? Express your answer as a common fraction.

Question

oobleck · Accepted Answer

are you sure about the 144?

Reiny · Answer

3 cases: BB ---> (5/12)(5/12) = 25/144 RR ---> (4/12)(4/12) = 16/144 YY ---> (3/12)(3/12) = 9/144 add them up

Reiny · Answer

Misread the question, read it as 'of the same colour.' So we need 1 - (25/144 + 16/144 + 9/144)