<PRE><B>Question 346965</B>
A recent sales trip that covered 1800 miles required 51 gallons of gasoline. 
Assuming that the advertised mileage estimates were correct, how many miles were driven in the city?
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Let x be the city miles.
Then 1800-x are the highway miles.
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distance/miles per gallon = gallons
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Equation:
gallons + gallons = 51 gallons
x/25 + (1800-x)/40 = 51 gallons
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Multiply thru by 25*40 to get:
40x + 25*1800 - 25x = 51*25*40
15x = 6000
x = 400 (miles of city driving)
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