Michael drove to a friends house at a rate of 40mph He retur

Michael drove to a friend\'s house at a rate of 40mph. He returned by the same route at a rate of 45mph. The driving time for the round trip was 4 hours. What is the distance Michael traveled?

Solution

D=RT
D=45T
D=40(4-T)
BECAUSE THE DISTANCES ARE THE SAME WE HAVE:
45T=40(4-T)
45T=160-40T
45T+40T=160
85T=160
T=160/85
T=1.882 HOURS FOR THE 45 MPH TRIP.
4-1.882=2.118 HOURS FOR THE 40 MPH TRIP.
D=45*1.882=84.7 MILES IS THE ONE WAY DISTANCE.
D=40*2.118=84.7 DITTO.
TOTAL DISTANCE TRAVELEDIS:
2*84.7=169.4 MILES.