<PRE><B>Question 147693</B>
 There are 20 kilograms of a solution that is 10% salt. How many kilograms of salt must be added to make a solution that is 25% salt?
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EQUATION:
salt + salt = salt
Let x be the amount of pure salt that must be added.
0.10(20) + x = 0.25(20+x)
2 + x = 5 + (1/4)x
(3/4)x = 3
x = 4 kg (amt. of pure salt that must be added.
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Cheers,
Stan H.</PRE>