SOLUTION: two cars leave town at the same time going the same direction. One travels 30 mph and the other 46 mph. In how many hours will they be 72 miles apart?

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Question 392527: two cars leave town at the same time going the same direction. One travels 30 mph and the other 46 mph. In how many hours will they be 72 miles apart?
Found 2 solutions by richard1234, stanbon:
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
Relative to the first car, the second car (the faster one) travels 16 mph. It takes 4.5 hours to cover a displacement of 72 miles (since 72/16 = 4.5), so 4.5 hours.

The standard way simply uses a bit of elementary algebra. At some time t, 30t and 46t will be separated by 72 miles. Therefore,

46t - 30t = 72 mi

16t = 72

t = 4.5 hr

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
two cars leave town at the same time going the same direction. One travels 30 mph and the other 46 mph. In how many hours will they be 72 miles apart?
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Each hour the faster car will gain 46-30 = 16 miles on the slower car.
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Equation:
distance/rate = time
72/16 = 4 1/2 hours
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Cheers,
Stan H.