Question 87507: During rush hour, Adriana can drive 20 miles using the side roads in the same time that it takes to travel 15 miles on the freeway. If Adriana's rate on the side roads is 10 mi/h faster than her rate on the freeway, find her rate on the side roads.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! During rush hour, Adriana can drive 20 miles using the side roads in the same time that it takes to travel 15 miles on the freeway. If Adriana's rate on the side roads is 10 mi/h faster than her rate on the freeway, find her rate on the side roads.
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Side Road DATA:
distance = 20 miles ; rate = x mph ; time = d/r =20/x hrs.
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Freeway DATA
distance = 15 miles ; rate = x-10 mph ; time = d/r = 15/(x-10) hrs
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EQUATION:
time = time
20/x = 15/(x-10)
4(x-10) = 3x
x = 40 mph (rate on the side roads
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Cheers,
Stan H.
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