Consider a lab rat in a maze. There are four paths that can be taken with equal probability. Path A leads to exit in 5 minutes. Path B leads back to start and takes 8 minutes. Path C leads to exit in 3 minutes and last path D is 2 minutes long and leads back to start. What is the expected escape time of this poor rat from the maze?
t = (1/4)*5 + (1/4)*(8+t) + (1/4)*3 + (1/4)*(2+t) t = 9