SOLUTION: Imogene's car traveled 210 mi averaging a certain speer. If the car had gone 5mph faster, the trip would have taken 1 hour less. Find the average speed.
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Question 901177: Imogene's car traveled 210 mi averaging a certain speer. If the car had gone 5mph faster, the trip would have taken 1 hour less. Find the average speed. Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Imogene's car traveled 210 mi averaging a certain speer. If the car had gone 5mph faster, the trip would have taken 1 hour less. Find the average speed.
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Actual DATA:
distance = 210 miles ; time = x hrs ; rate = d/t = 210/x mph
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Modified DATA:
distance = 210 miles ; time = x-1 hrs ; rate = d/t = 210/(x-1) mph
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Equation:
210/(x-1) - 210/x = 5 mph
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210x - 210(x-1) = 5x(x-1)
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210 = 5x^2 - 5x
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42 = x^2 - x
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x^2 - x - 42 = 0
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Factor::
(x-7)(x+6) = 0
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Positive solution::
Ans:: x = 7 hours
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Cheers,
Stan H.
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