<PRE><B>Question 24136</B>
&lt;p&gt;Call the 70% solution A, and the 18% solution B&lt;/p&gt;

&lt;p&gt;Solution B provides you with {{{0.18*60=10.8}}} units of salt in 60 units. For every unit of solution A you add, you get 0.7 units of salt. This is just the definition of percentages.&lt;/p&gt;

&lt;p&gt;So, when adding x units of solution A we get {{{10.8 + 0.7x}}} units of salt, and we have {{{60+x}}} gallons, so the percentage salt in the finished solution is:&lt;/p&gt;

{{{(10.8+0.7x)/(60+x)}}}

&lt;p&gt;We want this to equal 60%, or 0.6, so we have to solve the equation:&lt;/p&gt;

{{{(10.8+0.7x)/(60+x)=0.6}}}

&lt;p&gt;Unfortunately, I&#39;m not clever enough to make the automatic solver, solve that. But if you multiply both sides by {{{60+x}}} and then put it through the automatic solver it works. See below:&lt;/p&gt;

*[invoke explain_simplification &quot;10.8+0.7*x=36+0.6*x&quot;]

&lt;p&gt;And you get the answer 252. Don&#39;t forget to check it by putting your answer back into the equation!&lt;/p&gt;

&lt;p&gt;Hope this helps&lt;/p&gt;

&lt;p&gt;Kev&lt;/p&gt;</PRE>