Question 897499
 How many liters of an 8% solution of salt should be added to a 24% solution in order to obtain 560 liters of an 16% solution? 
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Here's simple method, you don't even need a chart.
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Let x = amt of 24% solution required
The resulting total is to be 560 liters, therefore
(560-x) = amt of 8% solution
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A simple mixture equation using the decimal equiv of the percent values
.24x + .08(560-x) = .16(560)
.24x + 44.8 - .08x = 89.6
.24x - .08x = 89.6 - 44.8
.16x = 44.8
x = 44.8/.16
x = 280 liters of the 24% solution
but they want to know the the amt of the 8% solution
560 - 280 = 280 liters of the 8% solution