Answer:
The correct answer is: x = 35 gallons
Explanation:
We will make equation for this problem:
20 x + 70 · 15 = (x + 15) · 35 => 20 x + 1050 = 35 x + 525 =>
35 x - 20 x = 1050 - 525 => 15 x = 525 => x = 525/15 = 35 gallons
x = 35 gallons
God with you!!!