Answer:
4 2/3 gallons of gas
Explanation:
Step 1
Suppose a car gas tank holds 21 gallons of gas.
On a trip it uses 2/3 of a tank of gas on a trip.
= 2/3 × 21 gallons of gas
= 14 gallons of gas
Step 2
Then it uses 1/3 of what is left in the tank.
The number of gallons of gas left =
21 gallons of gas - 14 gallons of gas
= 7 gallons of gas
Hence, this is calculated as:
1/3 × 7 gallons of gas
= 2 1/3 gallons of gas
Step 3
How many gallons of gas are left in the tank?
This is calculated as:
7 gallons of gas - 2 1/3 gallons of gas
= 7/1 - 7/3
Lowest common denominator =
= 21 - 7/3
= 14/3
= 4 2/3 gallons of gas is left
Therefore, 4 2/3 gallons of gas is left.