Question

to clean the fish tank 3/4 cups of disinfectant is needed for every two gallons of water how many cups of disinfectant are needed for 20 gallons of water

Answer 1

7 1/2 cups

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