Question 1135649
 a solution mixed at a concentration of {{{5 (g/ml)}}} and need {{{100 }}}gal mixed at {{{4( g/ml)}}}

{{{C[1]*V[1]=C[2]*V[2]}}}
{{{5*V[1]=4*100}}}
{{{V[1]=400/5}}}
{{{V[1]=80}}}


notice the product on both sides have same amount of substance ({{{g}}})

so, {{{80 }}}gal of the {{{5( g/ml)}}} solution has same amount of substance as {{{100}}} gal of {{{4 (g/ml)}}} solution


now take {{{80}}} gal of the {{{5( g/ml)}}} and {{{20}}} gal of water to make {{{100}}} gal of {{{4( g/ml )}}}solution


adding water does not change the amount of grams of substance, it just dilutes the concentration