Question

A car got 33 miles per gallon using gasoline that cost $2.95 per gallon. approximately what was the cost, in dollars, of the gasoline used in driving the car 350 miles? A: $10 B: $20 C: $30 D: $40 E: $50

Answer 1

$31.27

Explanation:

This is mainly a "units" problem: we need to figure out what multiplies or divides by what to leave "dollars" as the units.

The first place to start is how many gallons the car needs to go the distance, given its efficiency.

If we divide "miles" by "miles per gallon", then "miles" will cancel out and leave "gallons." Like this:

x miles ÷ y miles/gallon

Remember how when you're dividing by a fraction you get to flip it and multiply? That's how "miles" cancel out and "gallons" moves to the top.

So:

350 miles ÷ 33 miles/gallon = 10.6 gallons

The car will consume 10.6 gallons to go 350 miles.

(We can check our work by multiplying 10.6 by 33. Should get 350.)

So now it's a simple matter of figuring out how much that amount of gas costs. Sounds like a multiplication problem:

10.6 gallons times 2.95 $ per gallon

"Gallons" cancel out, leaving "dollars" as the unit:

10.6 x 2.95 = $31.27

In words: you'd have to spend $31.27 to buy 10.6 gallons of gas to go 350 miles in a car that gets 33 mpg.