Question 342922
In order to halve the concentration, double the volume of water.
Add 30 quarts of water.
Algebraically, here's the concentration equation,
Let A be the amount of water added.
Water is a 0% alcohol solution.
{{{0(A)+40(30)=20(A+30)}}}
{{{1200=20A+600}}}
{{{20A=600}}}
{{{highlight(A=30)}}}quarts