Question

Five days a week, you carpool with 3 co-workers and take turns driving each week. It is 14 miles from your home to your office. When you drive the carpool you must go an extra 4 miles to pick up your co-workers. If your car averages 18 miles per gallon, about how many gallons of gas should you save every 4 weeks by carpooling?

Answer 1

you will save 10 gallons

Answer 2

You will save 21.11 gallons of gas every 4 weeks by carpooling.

Explanation:

It is 14 miles from your home to your office. Means 28 miles total while returning.

And if there is no carpool, you will drive =
`28*5*4=560` miles

And amount of gas used will be =
`(560)/(18)=31.11` gallons

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Now, when you are car pooling, you will save the cost for three weeks means you will take out your car for 1 week only.

But you have to go additional 8 miles (including dropping off the co worker)

So, the total journey for 1 day will be of
`14+14+4+4=36` miles

Hence, for 1 week, you will drive :
`36*5*1=180` miles.

Gallons of gas used =
`(180)/(18)=10` gallons

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So, gallons of gas saved =
`31.11-10=21.11` gallons

Hence, you will save 21.11 gallons of gas every 4 weeks by carpooling.