Answers

2016-03-20T15:10:41+08:00
    Original solution must be equal to final solution
   thus
               200 x .6  =      0.7 w        /  60% =  .6  &   70%  = .7
                 w =  200 x 0.6/ 0.7
                     =  171.43 gm
             wt of evaporated water =   200- 171.43   ~  28.57gm
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