Problem Solving

The figure shown represents a board with four rows of pegs, and at the bottom of the board are four cells numbered 1 to 4. Whenever the ball shown passes through the opening between two adjacent pegs in the same row, it will hit the peg directly beneath the opening. The ball then has probability 1/2 of passing through the opening immediately to the left of that peg and probability 1/2 of passing through the opening immediately to the right. What is the probability that when the ball passes throught the first two pegs at the top it will end up in cell 2?

sorry, no figure shown for this...

but the answer is 3/8... please help me figure this one out.

Thanks.

There are three ways the ball will row into Cell 2. LRL, LRR, RLL. For each way, the probability of landing in the Cell in that order is ½ * ½ * ½ = 1/8, since there are 3 ways, 3*(1/8).