Question 1063952

Let x = number of liters of alcohol to be added

then  x+2 = final number of liters of alcohol
and  28+x+2 = final number of liters of liquid in mixture (i.e. water AND alcohol)

   (x+2)/(28+x+2) = 0.125
   (x+2)/(x+30) = 0.125
   x+2 = (0.125)(x+30)
   x+2 = 0.125x + 3.75
    0.875x = 1.75
             x = 1.75/0.875 = 2.

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Ans:  Adding {{{highlight(2)}}} liters of alcohol will make the mixture 12.5% alcohol
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Check:    (2+2)/(28+2+2) = 4/32 = 0.125 = 12.5%  (ok)