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?
A. 200r
B. 2(200 + r)
C. 10r

Answer 1

Answer:

Step-by-step explanation:

Let the speed of the car be "X". From 3 am until 1 pm (10 hours), the car will travel 10*X miles. 

The speed of the airplane is (X +200). From 11 am until 1 pm (2 hours), the plane will travel 2*(X+200). 

The distance travelled is the same, so: 

10*X = 2*(x+200)= 2x+400 

Subtract 2*X from both sides: 

8*X = 400

X = 400/8 = 50 mph.