SOLUTION: A private plane takes 8 hours less to travel 960 km than a car. If the plane travels 3 times as fast as the car, what is the speed of the plane and car?

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Question 1110288: A private plane takes 8 hours less to travel 960 km than a car. If the plane travels 3 times as fast as the car, what is the speed of the plane and car?
Found 3 solutions by josgarithmetic, ikleyn, greenestamps:
Answer by josgarithmetic(39614)   (Show Source):
You can put this solution on YOUR website!

SPEED TIME DISTANCE PLANE 3r 960/(3r) 960 CAR r 960/r 960 DIFFERENCE 8

Solve for r and evaluate 3r.

You can take a step, ,...

Answer by ikleyn(52756)   (Show Source):
You can put this solution on YOUR website!
.

- = 8 } = 8 r = = = 80. Answer. The speed of the car is 80 km/h. The speed of the plane is 3*80 = 240 km/h.

Answer by greenestamps(13195)   (Show Source):
You can put this solution on YOUR website!

The two other tutors who answered your question both used exactly the same traditional algebraic approach.

Of course, that is a valid approach. But here is a non-traditional approach that I like to use in problems like this, where the distances are the same.

The plane travels 3 times as fast as the car, so it takes 1/3 as long to make the trip.

So let x be the number of hours it takes the plane to make the trip; then 3x is the number of hours it takes the car. Then, since the plane takes 8 hours less than the car,

The plane takes 4 hours to travel the 960km, so its speed is 960/4 = 240 km/hr.

That is 3 times the speed of the car, so the speed of the car is 240/3 = 80 km/hr.