How much of a 50% alcohol solution should we mix with 10 gallons of a 35% solution to get a 40% solution?
Let x is the amount of 50% solution which we need. It means that there will be gallons of the 40% solution once we're done mixing the two.
Following is the basic work equation for this problem.
Now, plug in the volumes & solve for x.
0.5x + 0.35 (10) =0.4 ( x + 10)
0.5x + 3.5 + 0.4x + 4
0.1x + 0.5
x =0.5/0.1 = 5 gallons
Thus, we required 5 gallons of the 50% solution to get a 40% solution.