Begin, to knowing that,Originally Posted byBrooke

Solution 1has 55% of x gallons is glycerine which is gallons.

Solution 2has 20% of 15 gallons is glycerine which is gallons.

Thus when you combine them,

you have is amount of glycerine.

and, in total you have,

And you want 40% thus,

Thus,

Thus,

Thus,

Thus,