Question

Regions $A, B, C, J$ and $K$ represent ponds. Logs leave pond $A$ and float down flumes (represented by arrows) to eventually end up in pond $B$ or pond $C$. On leaving a pond, the logs are equally likely to use any available exit flume. Logs can only float in the direction the arrow is pointing. What is the probability that a log in pond $A$ will end up in pond $B$?

Answer 1

5/18

Explanation:

There is a 1/3 chance of going to k. From K, there is a 1/2 chance of going to b, so that way has a prob of 1/6. By the same concept, there is a 1/9 chance of going to B via J. The prob you are asking for is 5/18

Answer 2

Explanation:

1 1/5