Suppose there are four routes from North Point to Boulder Creek, three routes from Boulder Creek to Beaver Dam, three routes from Beaver Dam to Star Lake, and two routes directly from Boulder Creek to Star Lake. (Hint: Draw a sketch. Assume each route can only visit a city at most one time.) (a) How many routes from North Point to Star Lake pass through Beaver Dam?
(b) How many routes from North Point to Star Lake bypass through Beaver Dam?