<PRE><B>Question 785174</B>
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
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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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