Question

A plane can fly 520 miles in the same time as it takes a car to go 200 miles. If the car travels 80 mph slower than the plane, find the speed of the plane.

Answer 1

Answer: the speed of the plane is 130 mph

Step-by-step explanation:

Let x represent the speed of the plane. If the car travels 80 mph slower than the plane, then the speed of the car would be (x - 80) mph.

Time = Distance/speed

plane can fly 520 miles in the same time as it takes a car to go 200 miles. This means that the time it takes the plane to fly 520 miles is

520/x

Also, the time it takes the car to drive 200 miles is

200/(x - 80)

Since the time is the same, it means that

520/x = 200/(x - 80)

Cross multiplying, it becomes

520(x - 80) = 200 × x

520x - 41600 = 200x

520x - 200x = 41600

320x = 41600

x = 41600/320

x = 130 mph