Answer:
You need to mix 18 quarts of sparkling water
Explanation:
A recipe for sparkling grape juice calls for
quarts of sparkling water and
quart of grape juice.
Ratio of sparkling water to grape juice =

Let the amount of sparkling water be x
We are given that amount of grape juice is 9 quarts
So, Ratio of sparkling water to grape juice x:9
So,




Hence you need to mix 18 quarts of sparkling water