please helps me to solve the question 3c. The answer is 2/9 but i do not know how to get that...T_T
Let R be a right move: $\displaystyle P(R)=\frac{2}{6}$.
Let L be a left move: $\displaystyle P(L)=\frac{4}{6}$.
To end at B in three moves, we need RRL, RLR, or LRR.
Each of those has the same probability and $\displaystyle P(RRL)=\frac{2}{6}\cdot \frac{2}{6}\cdot\frac{4}{6}$