Question 121672
rt=d
45t=90
45t/45=90/45
t=2 hrs going.
.
3h 40m-2h=1h 40m=1 2/3h=5/3h time of return trip.
5r/3=90
5r/3 * 3/5=90* 3/5
r=54 mph rate of return.