Question 720803
how much pure antifreeze must be added to 20 L of a solution thaT IS 60% antifreeze to make a solution that is 80% antifreeze
<pre>
                                    Percentage           Liters of         
                   Liters of        expressed as      pure antifreeze
                    liquid           a decimal          in the liquid               
first solution         20              .60               .60(20)
added solution          x             1.00               1.00x  
--------------------------------------------------------------------------
final solution        20+x             .80              .80(20+x)

The equation comes from:
         {{{(matrix(8,1,

Liters,of,pure,antifreeze,in,the,first,solution))}}}{{{""+""}}}{{{(matrix(8,1,

Liters,of,pure,antifreeze,in,the,second,solution))}}}{{{""=""}}}{{{(matrix(8,1,

Liters,of,pure,antifreeze,in,the,final,solution))}}}

                  .60(20) + 1.00x = .80(20+x)

Solve that and get x = 20 liters.

Edwin</pre>