Question

Tom and his friend are driving to Louisville, Kentucky, next week. They figure that the trip will be about 432 miles round trip. If his car gets 31 mpg and the current cost of gasoline is $2.79, how much will they spend on gas?$51.61 $44.46$38.88 $31.00​ in progress 0 3 days 2021-07-20T04:48:10+00:00 2 Answers 2 views 0 ## Answers ( ) 1. Answer: The answer is$38.88.

2. ### Answer:  \$38.88  (choice C)

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Explanation:

Let x be the number of gallons used up. It’s some positive real number.

We’ll use the formula

miles = (mpg)*(number of gallons)

to help figure out how much fuel is used. The trip is 432 miles, and the mpg rating is 31

So,

miles = (mpg)*(number of gallons)

432 = 31*x

31x = 432

x = 432/31

x = 13.9354838709678  which is approximate.

Multiply that with the 2.79 to get the final answer.

2.79*x = 2.79*13.9354838709678 = 38.8800000000001

The 1 at the very end is probably due to some rounding error, but then again it may be accurate. Either way, that value rounds to 38.88

Side note: The 31 mpg rating is very likely an average value and not the same throughout the trip. This is due to the car changing speeds at different points of the journey. In reality, the true answer will vary slightly from the 38.88 figure we just calculated (but it should be fairly close).