Alright, lets get started.
The initial value = 83 gallons
The last value = 25 gallons
The change in value = 83 - 25
The change in value = 58 gallons
We need to find the change in percent
The formula for percent = change / initial value * 100
So, the percent change = 58 / 83 * 100
So, the percent change = 69.8795 %
Rounding to nearest tenth
the percent change = 69.9 % : Answer
Hope it will help :)