Question 782912
75% phosphoric acid is about 11.67 pounds per gallon.  The percentage is expected weight per weight.
Water is 8.345 pounds per gallon.


Let w = how many pounds of water to add.


{{{11.67*0.75/(w+11.67)=0.06}}}, as decimal fractions instead of as percents.
{{{6(w+11.67)=11.67(75)}}}
{{{6w=(11.67)(75)-6(11.67)}}}
{{{6w=11.67(75-6)}}}
{{{6w=11.67(69)}}}
{{{w=(11.67)(69)/6}}}
{{{highlight(w=134)}}} pounds of water.

As volume, {{{134/8.345=highlight(16.1)}}} gallons of water.