A car is driving down a road at a normal speed of 50 mph. It enters a hilly area of gradual incline and decline, where it must drive 50 miles uphill 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.
A. 24 mph
B. 32 mph
C. 37 mph
D. 12.5 mph