What is the probability that an F2 offspring will be tall with green pods?

Use all of the probabilities of getting one green and two yellow seeds in the bunch.

So:

G, Y, Y = 1/4 X 3/4 X 3/4 = 9/64

Y, G, Y = 3/4 X 1/4 X 3/4 = 9/64

Y, Y, G = 3/4 X 3/4 X 1/4 = 9/64

Add all the probabilities together.

9/64 + 9/64 + 9/64 = 27/64.

27/64 is the probability that three F2 seeds chosen at random will include one green seed and two yellow seeds.