Question

The average speed of one airplane is 200 mph faster than that of an automobile. If the automobile starts at 3 a.m. and the airplane starts from the same place at 11 a.m., they will have traveled the same number of miles by 1:00 p.m.

If r represents the rate of the automobile, how many miles does the plane travel?

Answer 1

time for airplane = 11 am to 1 pm = 2 hr
distance travelled by plane = 2a ------- (speed of plane is a mph)

time for auto = 3 am to 1 pm = 10 hr
distance travelled by plane = 10(a – 200)

2a = 10(a – 200)
8a = 2000
a = 250 mph ----- plane
and 250 – 200 = 50 mph ----- auto