SOLUTION: how many quarts of pure antifreeze must be added to 4 quarts of a 30% antifreeze solution to obtain a 60% antifreeze solution?

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Question 671405: how many quarts of pure antifreeze must be added to 4 quarts of a 30% antifreeze solution to obtain a 60% antifreeze solution?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
how many quarts of pure antifreeze must be added to 4 quarts of a 30% antifreeze solution to obtain a 60% antifreeze solution?
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Equation:
alcohol + alcohol = alcohol
1.0x + 0.30*4 = 0.60(x+4)
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100x + 30*4 = 60x + 60*4
40x = 30*4
x = 3 quarts (amt. of pure antifreeze needed)
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Cheers,
Stan H.