SOLUTION: Sarah walked north at the rate of 3mph and returned at the rate of 4mph. How many miles did she walk if the round trip took 3.5 hours?

Question 785174: Sarah walked north at the rate of 3mph and returned at the rate of 4mph. How many miles did she walk if the round trip took 3.5 hours?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Sarah walked north at the rate of 3mph and returned at the rate of 4mph. How many miles did she walk if the round trip took 3.5 hours?
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Equations:
n + s = 3.5 hours
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North distance:: rate*time = 3n miles
South distance:: rate*time = 4s miles
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Total distance = 3n+4s
===========================
North DATA:
rate = 3 mph ; time = x hrs ; distance = 3x miles
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South DATA:
rate = 4 mph ; time = 3.5-x hrs ; distance = 4(3.5-x) miles
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Equation:
3x = 14 - 4x
7x = 14
x = 2 hrs
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Total distance = 3x+(14-4x) = 6+(14-8) = 12 miles
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Cheers,
Stan H.
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