<PRE><B>Question 1163287</B>
you would solve this by looking at the number of gallons consumed driving in the city number of gallons consumed driving on the highway.
your equations are:
c + h = 6000
c/20 + h/30 = 6000/25
c is the number of miles driven in the city.
h is the number of miles driven on the highway.
multiply both sides of the second equation by 20 * 30 = 600; simplify, and leave the first equation as is to get:
c + h = 6000
30 * c + 20 * h = 144,000
multiply both sides of the first equation by 30 and leave the second equation as is to get:
30 * c + 30 * h = 180,000
30 * c + 20 * h = 144,000
subtract the second equation from the first to get:
10 * h = 36,000
solve for h to get:
h = 3600
since c + h = 6000, then you get:
c = 2400
h = 3600
the number of gallons consumed driving in the city are 2400/20 = 120.
the number of gallons consumed driving on the highway are 3600/30 = 120.
total gallons consumed are 240.
average miles per gallon for the whole trip are 6000/240 = 25.
solution looks good, and is:
2400 miles were driven in the city.

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