SOLUTION: How many cups of grapefruit juice must be added to 20 cups of a punch that is 10% grapefruit juice to obtain a punch that is 25% grapefruit juice? You will impress me extra, if you

Question 608055: How many cups of grapefruit juice must be added to 20 cups of a punch that is 10% grapefruit juice to obtain a punch that is 25% grapefruit juice? You will impress me extra, if you include your work. Hint: you do not end with twenty cups of punch.
Found 2 solutions by scott8148, josmiceli:
Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
(10%)(20) + x = (25%)(20 + x)
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Hope this is impressive
Let = cups of grapefruit juice that needs to be added
= cups of grapefruit juice in 20 cups of 10% punch
( the part that isn't grapefruit juice might be water, but that
doesn't really matter )
----------------

You must add 4 cups of grapefruit juice
check:

OK
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