Question 554802
How many liters of a 70% alcohol solution must be added to 50 liters of a 40% alcohol solution to produce a 50% alcohol solution? 
:
Let x = amt of 70% solution required
:
A typical mixture equation
:
.70x + .40(50) = .50(x+50)
.70x + 20 = .50x + 25
.70x - .50x = 25 - 20
.20x = 5
x = {{{5/.2}}}
x = 25 liters of 70% solution
:
:
check this
.7(25) + .4(50) = .5(25+50)
17.5 + 20 = 37.5