Question 995189
Keep all volume units as GALLONS or their fractions, and keep track of how much volume of the antifreeze (as if pure) and the water.


The Quart:
{{{(1/3)(1/4)*gallon}}} antifreeze
{{{(2/3)(1/4)*gallon}}} water


The Half-Gallon:
{{{(3/4)(1/2)*gallon}}} antifreeze
{{{(1/4)(1/2)*gallon}}} water


ALL COMBINED
-
Antifreeze, {{{(1/3)(1/4)+(3/4)(1/2)}}}
{{{1/12+3/8}}}
{{{2/24+9/24}}}
{{{11/24}}}
Water, {{{(2/3)(1/4)+(1/4)(1/2)}}}
{{{2/12+1/8}}}
{{{4/24+3/24}}}
{{{7/24}}}
-
This new combined mixture is  {{{11/24}}} gallons antifreeze and {{{7/24}}} gallons water.  Ratio of antifreeze to water is  <b>11:7</b>.