Question

A plane can fly 420 miles in the same time as it takes a car to go 150 miles. If the car travels 90 mph slower than the plane, find the speed of the plane. Using r as your variable to represent the speed of the plane in miles per hour, write an equation using the information above that can be solved to find the answer to this problem.

Answer 1

Explanation:

rate of the plane be x

distance traveled by plane = 420 miles

time taken by plane = 420/x

distance traveled by car =120 miles

rate of car = x-120

time taken by car = 120 / x-100

the time taken by both are same

420/x = 120/ x-100

420(x-100)=120x

420x-42000 = 120x

420x-120x=42000

300x= 42000

x=42000/300

x=140 mph the speed of the plane