SOLUTION: A plane can fly 390 miles in the same time as it takes a car to go 150 miles. If the car travels 80 mph slower than the plane, find the speed of the plane.
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Question 1060104: A plane can fly 390 miles in the same time as it takes a car to go 150 miles. If the car travels 80 mph slower than the plane, find the speed of the plane. Answer by ikleyn(52884) (Show Source):
You can put this solution on YOUR website! .
A plane can fly 390 miles in the same time as it takes a car to go 150 miles. If the car travels 80 mph slower than the plane,
find the speed of the plane.
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Let "u" be the speed of the plane under the question, in mph.
Then the car' speed is (u-80) mph.
The equation is
= .
To solve it, multiply both sides by u*(u-80). You will get
390(u-80) = 150u,
390u - 390*80 = 150u,
390 - 150u = 390*80,
240u = 31200, ---> u = = 130.
Answer. The speed of the plane is 130 miles per hour.
