Question

Calculate how much 30% alcohol solution and 80% alcohol solution must be mixed to end up with exactly 14 gallons of a 40% alcohol solution. You'll need ____ gallons of the 80% solution.

Answer 1

You'll need 2.8 gallons of the 80% solution.

Explanation:

Let the volume of 30% alcohol =x gallons

Then the volume of 80% alcohol =(14-x) gallons

Since we want to obtain a 40% alcohol solution, we have:

0.3x+0.8(14-x)=0.4(14)

0.3x+11.2-0.8x=5.6

0.8x-0.3x=11.2-5.6

0.5x=5.6

x=11.2

Therefore, the volume of 80% alcohol

=14-11.2

=2.8 gallons

You'll need 2.8 gallons of the 80% solution.