<PRE><B>Question 203796</B>
A girl walked 1/3 of the way at 3 mph and got a car ride the rest of the way at 30 mph. What was her average speed?
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average speed = total distance/total time
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Your Problem:
Let the total trip distance be x miles:
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Walking time = distance/rate = [(1/3)x]/[3 mph] = x hrs
Riding time = distance/rate = [(2/3)x]/[30 mph] = 20x hrs.
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Therefore average speed = x miles/(21x hrs) = (1/21) mph
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Cheers,
Stan H.</PRE>