Question 272177
A woman hikes to the bottom of the Grand Canyon at a rate of 4.5 mph and returns to the top by mule at a rate of 2.5 mph. If the total time of the trip is 7 hours, how long did she walk and what was the total length of her trip?
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Down DATA:
rate = 4.5 mph ; distance = x miles ; time = x/4.5 hrs 
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Up DATA:
rate = 2.5 mph ; distance = x miles ; time = x/2.5 hrs
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Equation:
time + time = 7 hrs
x/(9/2) + x/(5/2) = 7
Multiply thru by 45 to get:
10x  + 18x = 45*7
28x = 45*7
4x = 45
x = 45/4 miles = 11 1/4 miles (length of her trip)
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Walking time = (45/4)/(9/2) = (45/4)(2/9) = 5/2 = 2.5 hrs
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Cheers,
Stan H.