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Question 260107: a SUV gets 18 mpg in city, 24 mph on highway. the SUV is driven 329 miles on 15 gallons of gas. How many miles were on city driving, and highway driving
18x + 24y = 329
x +y = 15
18x + 24(15 -x) = 329
18x + 360 - 24x = 329
-6x = -31
x = 5.16
18(5.16)+ 24 y = 329
92.88 + 24y = 329
24y = 236.12
y = 9.8
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! a SUV gets 18 mpg in city, 24 mph on highway. the SUV is driven 329 miles on 15 gallons of gas. How many miles were on city driving, and highway driving
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miles equation: c + h = 329
gallons equation: c/18 + h/24 = 15
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Modify the equations:
Multiply thru the 2nd equation by 72:
Multiply thru the 1st equation by 4:
4c + 4h = 4*329
4c + 3h = 72*15
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Subtract the 2nd from the 1st and solve for "h":
h = 236 miles (# of highway miles driven)
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c = 329-236 = 93 miles (# of city miles)
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Cheers,
Stan H.
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