SOLUTION: A tank holds 140 liters of a chemical solution. Currently, the solution has a strength of 40%. How much of this solution should be drained and replaced with 80% solution to get a

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Question 561580: A tank holds 140 liters of a chemical solution. Currently, the solution has a strength of 40%. How much of this solution should be drained and replaced with 80% solution to get a final strength of 60%
Answer by stanbon(75887) About Me  (Show Source):
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A tank holds 140 liters of a chemical solution. Currently, the solution has a strength of 40%. How much of this solution should be drained and replaced with 80% solution to get a final strength of 60%
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active - active + active = active
0.40*140 - 0.40x + 1*x = 0.60*140
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Multiply thru by 100 to get:
40*140 - 40x + 100x = 60*140
60x = 20*140
x = (1/3)140
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x = 46 2/3 liters (amt. of 40% that must be replaced)
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Cheers,
Stan H.
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