Trucks usually travel very slowly . A uphill B on flat roads C...

The road connecting two mountain villages goes only uphill or downhill. A bus always travels 15 mph...

A runner completes a 16 mile trip, running 8 miles uphill and 8 miles downhill in a total of 4 hours...

A train goes twice as fast downhill as it can go uphill, and 2/3 as fast uphill as it can go on leve...