The average rate on a round-trip commute having a one-way distance d is given by the compl...

The average rate on a round-trip commute having a one-way distance d is given by the complex rational expression

in which r1 and r2 are the average rates on the outgoing and return trips, respectively. Simplify the expression. Then find your average rate if you drive to campus averaging 40 miles per hour and return home on the same route averaging 30 miles per hour. Explain why the answer is not 35 miles per hour.