<PRE><B>Question 74505</B>
A tank holds 80 liters of a chemical solution. Currently the solution has a strength of 30%. How much of this solution must be drained and replaced with a 70% solution to get a strength of 40%?
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30% solution DATA:
Amt = 80 L ; amt of active ingredient = 0.3*80 = 24 L
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70% solution DATA:
Amt = x L ; amt of active ingredient = 0.7x L
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40% remainder DATA:
Amt = (80) L ; Amt of active ingredient = 0.4(80) = 32 L
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EQUATION:
active - active = active
24 + 0.7x = 32
0.7x = 8
x= 11.43 L
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Cheers,
Stan H.

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