A tank has a capacity of 120 gallons and is currently 85% filled. How many gallons remain to fill the tank?

To determine how many gallons remain to fill the tank, first calculate how much of the tank is currently filled. The tank has a total capacity of 120 gallons and is 85% filled.

To find out how many gallons are currently in the tank, multiply the total capacity by the percentage filled:

120 gallons * 0.85 = 102 gallons.

Next, subtract the amount of water currently in the tank from its total capacity to find out how much more water is needed:

120 gallons - 102 gallons = 18 gallons.

This indicates that there are 18 gallons remaining to fill the tank. Therefore, the correct answer is 18 gallons.