Question

The gas tank in the car holds 20 gallons of gasoline. You used up 4 gallons and 1 quart on your trip. How much gasoline is left in the tank?

Answer 1

There are 4 quarts in a gallon so the amount used can be shown as 4 1/4, or 4.25 so to find out how much gas is left in the tank you simply subtract 4.25 from 20.

20-4.25

=15.75

There is 15.75, or 15 3/4, gallons of gasoline left in the tank.

Answer 2

The correct answer is:

Total capacity of tank in quarts:

20 gallons = 20 × 4 = 80 quarts

Gasoline used in quarts:

4 gallons 1 quart = (4 × 4) + 1 = 17 quarts

Gasoline left in the tank in quarts:

80 − 17 = 63 quarts

Gasoline left in the tank in gallons and quarts:

63 quarts = 63 ÷ 4 = 15 remainder 3 = 15 gallons 3 quarts