Question 170500
In words:
(amount of weed killer) / (weed killer + H2O) = % solution
I start with 3 oz of 80% solution. In this 3 oz, there is
{{{.8*3 = 2.4}}} oz of weed killer.
Let {{{x}}}= amount of water to be added
I'm not adding weed killer, just water, so
{{{2.4 / (x + 3) = .2}}}
Multiply both sides by {{{x + 3}}}
{{{2.4 = .2*(x + 3)}}}
{{{2.4 = .2x + .6}}}
{{{.2x = 1.8}}}
{{{x = 9}}}
9 oz of water must be added to get a 20% solution
check:
{{{2.4 /(9 + 3) = .2}}}
{{{2.4/12 = .2}}}
{{{.2 = .2}}}
OK