Question 1164981
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how many qt. of 12% saline solution must be mixed with 4 qt. of pure water to make a 9% solution. ?
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<pre>
PERCENT CONC.     QUANTITY VOL.        SOLUTE
  12                   v                0.12v
   0 (water)           4 qts.            0
 ---------------------------------------------
   9                  v+4              0.09(v+4)
</pre>
The amount of solute from the parts must be same as amount from the finished solution.


{{{0.12v=0.09(v+4)}}}
-
{{{0.12v=0.09v+0.36}}}
{{{0.03v=0.36}}}
{{{highlight(v=12)}}}{{{quarts}}} of the 12% saline.