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Your car has a 12 gallon gas tank. you start off your week with a full tank. during the week you drive 145 miles.
on Saturday you decide to take a road trip so you add 6 gallons of gas to your tank and leave town.
you drive for 185 miles and your gas gauge reads exactly 1/4 full. what is your average gas mileage in miles per gallon?
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Instead of solving for the ratio I will solve the problem for the reciprocal ratio .
Then I will convert my answer to miles per gallon.
So, let x be the unknown ratio gallons-per-mile.
The full distance traveled is 145 + 185 miles = 330 miles.
The amount of the fuel spent is = 12 + 6 - 3 = 15 gallons.
Notice that is the volume of the gas that left in the tank.
From the other side, the amount of the fuel spent is 330*x gallons
It gives you an equation
15 = 330x.
Hence, x = = .
Therefore, the answer to the problem's question is 22 miles per gallon.
Solved.