<PRE><B>Question 549129</B>
How many gallons of 80% antifreeze must be added to 90 gallons of 20% antifreeze to get a mixture of 70% antifreeze?
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alcohol + alcohol = alcohol
0.20*90 + 0.80x = 0.70(90+x)
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Multiply thru by 100 to get:
20*90 + 80x = 70*90 + 70x
10x = 50*90
x = 450 gallong (amt. of 80% solution needed)
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Cheers,
Stan H.
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