Question

A man has an old truck that gets 15 miles per gallon. In January, he started using his bike to commute to and from work. He lives 9.8 miles away from his job site. Gasoline during the month averaged $3.75 a gallon. How much money did he save on gasoline if he rode his bike to and from work 18 times instead of driving?

Answer 1

To begin, you need to find the overall mileage he would have traveled. You can find this by taking 36 (the amount of total trips made) and multiplying it by 9.8 miles.

36 x 9.8 = 352.8

Divide 352.8 by the 15 miles per gallon, giving you 23.52 gallons.

Finally, multiply the gallons by the price ($3.75) and you will find your answer, which is $88.20.

Answer 2

lets calculate how many miles did he rode his bike, that would be 18 times 9.8 miles:
total miles = 18*9.8
total miles = 176.4
that is the total miles he rode his bike, now lets find out how many gallons that represents. If 15 miles equals a gallon, then how many gallons are 176.4 miles, we can solve that with a rule of three:
15 mi -----> 1 gal
176.4 mi --> x
x = (176.4)(1)/15
x = 11.76 gal
therefore he saved 11.76 gallons of gasoline by riding his bike 176.4 miles, and that represented an amount of dollars of:
11.76 * 3.75 = 44.1
that is because each gallon costs $3.75