Problema Solution

how many liters of a 10% alcohol solution must be mixed with 40 L of a 50% solution to get a 40% solution?

Answer provided by our tutors

Bottle A

   10% solution

   X liters

Bottle B

   50% solution

   40 liters 

bottle C (mixture)

   40% solution

   Xliters + 40liters

So the equation is:

      (10%)X + (50%)40 = (40%) (X+40)

                .1x + (.5)40 = .4(x+40)

                     .1x + 20 = .4x + .4(40)

                     .1x + 20 = .4x + 16

                    .4x - .1x = 20 - 16 

                            .3x = 4  

                             X = 4/.3 

                             X = 13.33 liters