Question

A car is driving down a road at a normal speed of 50 miles per hour. It enters a hilly area of gradual incline and decline, where it must drive 50 miles up hill and then 50 miles downhill. If this 100 mile section of road takes 2.6 hours to traverse instead of the expected 2 hours (the time it would take if the road was completely flat) determine the speed that the hills add or subtract when going over.

Answer 1

Explanation:

I'm going to assume that the car goes 50-x mph uphill and 50+x mph downhill.

x ≅ 24 miles per hour

26 mph uphill and 74 mph downhill