Solve
-A Car Travels 400 Miles on Level Terrain in the Same

Multiple Choice

Solve.
-A car travels 400 miles on level terrain in the same amount of time it travels 160 miles on mountainous terrain. If the rate of the car is 30 miles per hour less in the mountains than on level ground, find its rate in the mountains.

A) $50 \mathrm { mph }$
B) $80 \mathrm { mph }$
C) $40 \mathrm { mph }$
D) $20 \mathrm { mph }$