Question 741199
Let d = the distance one way
Let s = the speed on the outbound trip
The time for the outbound trip = 2 h
Since distance = speed x time, we can write for the two trips
d = s*2 -> s = d/2
d = (s-3)(2+0.5) [3 mph slower and 0.5 h longer]
d = (d/2-3)(2.5)
Solve for d:
d = 1.25d - 7.5
0.25d = 7.5
d = 30 mi
Therefore the round trip distance is 60 mi