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?

1 Answer
Apr 19, 2018

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.