Question

How many cup of juice must be added to 30 cup of punch that is 8% grapefruit juice, to obtain a punch that is 10% grapefruit?

Answer 1

0.67 cups

Explanation:

`(8/100) * 30 = 2.4` cups

So the other components of the punch are going to remain constant. Therefore, you have `30-2.4` cups (`27.6` cups) of other components. `27.6` are `92%` of the current punch. You want them to be `90%`. Therefore, `x * (90/100) = 27.6`,

Therefore, `x = 27.6 * (100/90) = 30.67`. Therefore, the answer is `0.67` cups of grapefruit.