A bag contains 2 yellow 12 red and 6 green marbles What is the probability of selecting a red marble replacing it then selecting another red marble?

The probability of drawing two reds, with replacement, is the same as the probability of drawing a red, times itself. So:

P(drawing two reds) = P(drawing a red)2 = (12/(2 + 12 + 6))2 = (12/20)2 = (3/5)2 = 9/25