Question 154183
How much water must be evaporated from 38 ounces of a 4% salt solution to make a 5% salt solution? 
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Let "x" be the amount of water that must be evaporated.
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EQUATION:
Salt: 0.04*38 - 0*x = 0.05(38-x)
1.52 = 1.9 -0.05x
-0.05x =-0.38
x = 8 ounces (amount of water that must be evaporated)
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Cheers,
Stan H.