A tree diagram with 8 possible outcomes. The outcomes are (H, H, H), (H, H, T), (H, T, H), (H, T, T), (T, H, H), (T, H, T), (T, T, H), (T, T, T). What is the probability of getting 2 heads up and 1 tails up when flipping three coins?

StartFraction 1 over 6 EndFraction
One-fourth
StartFraction 3 over 8 EndFraction
Two-thirds