Answer:
The amount of water to be added is ¹/₄ gallon
Step-by-step explanation:
Given;
amount of pure antifreeze at 100% = 1 gallon
let the amount of water to be added with 0% antifreeze = (x) gallon
then, the amount of mixture at 80% antifreeze = (x + 1) gallon
For conservation of mass, we will have the following equation;
(1 x 1) + (0)(x) = 0.8(x +1)
1 = 0.8x + 0.8
0.8x = 1 - 0.8
0.8x = 0.2
x = 0.2 / 0.8
x = ²/₈
x = ¹/₄ gallon
Therefore, the amount of water to be added is ¹/₄ gallon
