Step-by-step explanation:
A radio station's signal has a radius of 100 miles.
Diameter = 2 x 100 = 200 miles
If you drive at a constant speed of 40 miles an hour
Speed of vehicle = 40 miles per hour.
We have
Distance traveled = Speed X Time taken
200 = 40 X Time
Time = 5 hours
So after riding 5 hours the vehicle falls outside of signal range.
Option D is the correct answer.