An apple is located at vertex A of pentagon ABCDE, and a worm is located two vertices away, at C. Every day the worm crawls with equal probability to one of the two adjacent vertices. Thus after one day the Schr odinger's worm. worm is at vertex B or vertex D, each with probability 1 2 . After two days, the worm might be back at C again, because it has no memory of previous positions. When it reaches vertex A, it stops to dine. a What are the mean and variance of the number of days until dinner