Question

Drove from one town to next and back. 70 miles per hour there, 50 miles per hour back. Total drive time 12 hours. What's the distance between the towns?

Answer 1

350 miles

Explanation:

The relationship between time, speed, and distance is ...

time = distance/speed

If we let d represent the distance between towns, we have a total drive time of ...

d/70 + d/50 = 12

50d + 70d = 12(50)(70) . . multiply by 50·70

120d = 120(350) . . . . . . . simplify a bit

d = 350 . . . . . . . . . . . . . . divide by 120

The distance between towns is 350 miles.