Answer:
6
Explanation:
3/4=6/8
6/8-1/8=5/8
So 5/8 of the tank is 15 gallons. This means each 1/8 of a tank is 3 gallons.
The van is currently 6/8 full. We need to add another 2/8 to completely fill the tank.
2x3=6
You’ll need 6 more gallons to fill the tank.