<PRE><B>Question 153543</B>
How many kilograms of water must be evaporated from 50 kg of a 10% salt solution to obtain a 15% salt solution?
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EQUATION:
salt: 0.10*50 -0*x = 0.15(50-x)

Multiply thru by 100 to get rid of the decimals:

10*50 = 15(50-x)
500 = 750 - x 
x = 250 kg (amount of water that must be evaporated)
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Notice that this answer makes no sense; you cannot evaporate
250 kg when you only have 50 kg.
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Why the nonsense?
Notice that you started with a 10% solution, evaporated water,
and ended up with a 15% solution.  That cannot happen.
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Cheers,
Stan H.


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