Question 166784
In words:
(gallons of antifreeze in final solution)/(gallons of solution) = % antifreeze
Let {{{w}}}= the gallons of water to be added
The gallons of final solution will be
{{{30 + w}}}
Initially there is 70% antifreeze
{{{.7*30 = 21}}} gallons
{{{21 / (30 + w) = .6}}}
{{{21 = 18 + .6w}}}
{{{.6w = 3}}}
{{{w = 5}}}
5 gallons of water must be added to get a 60% solution
check:
{{{21 / (30 + w) = .6}}}
{{{21 / (30 + 5) = .6}}}
{{{21/35 = .6}}}
{{{.6 = .6}}}
OK