Solving a system of equations we can see that we need to use 120 ml of the 80% solution, and the other 80ml are of the 50% solution.
Let's define the variables:
We know that we want to make 200ml, then:
x + y = 200
And the concentration of these 200ml must be of 68%, then the concentrations in the left side and in the rigth side must give the same value, so we can write:
x*0.5 + y*0.8 = 200*0.68
(the concentrations are written in decimal form)
Then we have the system of equations:
x + y = 200
x*0.5 + y*0.8 = 200*0.68
To solve it we start by isolating x in the first equation:
x = 200 - y
Replacing that in the other equation we get:
(200 - y)*0.5 + y*0.8 = 200*0.68
Now we can solve this for y, we will get:
100 - y*0.5 + y*0.8 = 136
y*0.3 = 136 - 100 = 36
y = 36/0.3 = 120
So we need to use 120 ml of the 80% solution, and the other 80ml are of the 50% solution.
If you want to learn more about systems of equations:
https://brainly.com/question/13729904
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