Question 1144259
Depends the concentration of bleach available.  Is 12.5% available?  Is it 10% to start with?


Taking x parts of 12.5% by volume
then  1-x p parts by volume of just water


{{{12.5x+0=5(1-x)}}}
-
{{{12.5x=5-5x}}}
{{{7.5x=5}}}
{{{x=2/3}}}


Mix enough water with {{{2/3}}} quarts of 12.5% bleach to make 1 quart of finished solution.   (About {{{1/3}}} quart of water).