The distance between two cities is ninety miles, and a woman drives from one city to the other at a rate of 45 mph. at what rate must she return if the total travel time is three hours and forty minutes? 27 mph 45 mph 54 mph

The distance between two cities is ninety miles, and a woman drives from one city to the other at a rate of 45 mph. At what rate must she return if the total travel time is three hours and forty minutes?

1st leg DATA:
distance = 90 mi ; rate = 45 mph ; time = d/r = 2 hrs.
2nd leg DATA:
distance = 90 mi ; time = [3 2/3 - 2] = 1 2/3 hrs; rate = 90/(5/3) = 54 mph
Ans: 54 mph