SOLUTION: You drive to houston and back in 8 hours. Suppose your returning speed is 10mph slower than your going speed and that the total trip is 300 miles. What was your speed going to hous

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Question 201093: You drive to houston and back in 8 hours. Suppose your returning speed is 10mph slower than your going speed and that the total trip is 300 miles. What was your speed going to houston?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
You drive to houston and back in 8 hours. Suppose your returning speed is 10mph slower than your going speed and that the total trip is 300 miles. What was your speed going to houston?
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Note: Distance to Houston must be 150 miles
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To-Houston DATA:
distance = 150 mi ; rate = x mph ; time = 150/x hrs
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From-Houston DATA:
distance = 150 mi ; rate = x-10mph ; time = 150/(x-10)
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Equation:
time + time = 8 hrs.
150/x + 150/(x-10) = 8
150(x-10) + 150x = 8x(x-10)
300x - 1500 = 8x^2 -80x
8x^2 -380x + 1500 = 0
2x^2 - 95x + 375 = 0
x = [95 +- sqrt(95^2 - 4*2*375)]/4
x = 43.155 mph (rate to-Houston)
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Cheers,
Stan H.
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