SOLUTION: John has found that his new car gets 33 miles per gallon on the highway and 28miles per gallon in the city. He recently drove 343 miles on 11 gallons of gasoline. How many miles di

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: John has found that his new car gets 33 miles per gallon on the highway and 28miles per gallon in the city. He recently drove 343 miles on 11 gallons of gasoline. How many miles di      Log On


   

Question 1095983: John has found that his new car gets 33 miles per gallon on the highway and 28miles per gallon in the city. He recently drove 343 miles on 11 gallons of gasoline. How many miles did he drive on the highway? How many miles did he drive in the city?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
If R is for fuel efficiency in miles per gallon;
V is for volume of fuel in gallons;
D is for distance in miles,
A useful formula is RV=D, or R=D%2FV. 

Let v be how many gallons used in highway driving.

                    FUEL EFFICIENCY    VOLUME      DISTANCE

CITY                  28               11-v        28(11-v)

HIGHWAY               33               v            33v

Totals                                 11             343

highlight_green%2828%2811-v%29%2B33v=343%29-----basic equation to solve.
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308-28v%2B33v=343
5v=343-308
5v=35
v=7 and 11-v=4.

City Miles, 28%2A4=highlight%28112%29
Highway Miles, 33%2A7=highlight%28231%29

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You could assign a variable to one of the distances instead, and form an equation that way, using sum of the volumes.