Answer:
15 gallons
Explanation:
So the easiest way to solve this one is basic reasoning. It's easy to find 3/4 of a number if you know what 1/4 is.
20/4 = 5, or 1/4 of 20 = 5
3/4 is 3 times as much as 1/4, so 5(3)=15
Or, you can solve using a proportion
3 x
_ = _
4 20
(those are fractions)
Cross multipy
3 (20) = 4x
60 = 4x
Divide both sides by 4 to isolate the variable
15 = x
The final way to solve this is by converting the decimal to a fraction. 3/4 = 0.75
20 x 0.75 = 15