Answer:
7 1/2 cups
Step-by-step explanation:
20 gallons is ten times 2 gallons.
Ten times the amount of water will require ten times the disinfectant (we assume).
... 10 × 3/4 cup = 30/4 cups = 7 1/2 cups
IDK
search up yt vid or use https://www.mathpapa.com/algebra-calculator.html
X = 0.9
100