The average rate on a round-trip commute having a one-way distance d is given by the following complex rational expression in which r1 and r2 are the average rates on the outgoing and return trips, respectively. Simplify the expression. Then find the average rate if a person drives to campus averaging 52 miles per hour and returns home on the same route, averaging 36 miles per hour. Explain why the answer is not 44 miles per hour