SOLUTION: How many cups of grapefruit juice must be added to 30 cups of a punch that is 8% grapefruit juice to obtain a punch that is 10% grapefruit juice?

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Question 488315: How many cups of grapefruit juice must be added to 30 cups of a punch that is 8% grapefruit juice to obtain a punch that is 10% grapefruit juice?

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
How many cups of grapefruit juice must be added to 30 cups of a punch that is 8% grapefruit juice to obtain a punch that is 10% grapefruit juice?
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Equation:
grape + grape = grape
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x + 0.08*30 = 0.10(x+30)
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Multiply thru by 100 to get:
100x + 8*30 = 10x + 10*30
90x = 2*30
x = 2/3 of a cup of 100% grapejuice must be added.
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Cheers,
Stan H.