# Cecil averages 31 miles per gallon. He is driving 461 miles, filled tank with 16 gal of gas and no more after he left. How many gal are left arrived?

embizze | High School Teacher | (Level 2) Educator Emeritus

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Cecil fills is tank with 16 gallons of gas. He then drives 461 miles. Cecil gets 31mpg. How much fuel is left at the end of the trip?

To compute the amount of gas used we divide 461 by 31. Using unit analysis, we see that ` ``"miles"/("miles"/"gal")="gal" ` so the units are correct. Therefore, Cecil used `461/31~~14.87 ` gallons.

Since he started with 16 gallons, there are 16-14.87=1.13 gallons left after the trip.

As a check, with 16 gallons Cecil could drive 496 miles. (`31 "mpg"*16"gal"=496"miles" ` ). So he could have driven 35 more miles before running out of fuel. To find the remaining fuel take `(35"miles")/(31 "miles"/"gal")~~1.13"gal" `

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tonys538 | Student, Undergraduate | (Level 1) Valedictorian

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Can can drive 31 miles for each gallon of gas that he fills in the car. He initially fills 16 gallons of gas. This should allow him to travel for 16*31 = 496 miles.

If he travels 461 miles, the gas used during the journey is equal to 461/31.

Of the 16 gallons that he filled, the amount left at the end of the journey is 35/31 gallons.