Question 196090
Let {{{x}}}= liters of 10% acid solution needed
In words:
(liters of acid in final solution)/(total liters of solution) = 6%
{{{(.04*10 + .1x) / (10 + x) = .06}}}
Multiply both sides by {{{10 + x}}}
{{{.4 + .1x = .06*(10 + x)}}}
{{{.4 + .1x = .6 + .06x}}}
{{{.04x = .6 - .4}}}
{{{.04x = .2}}}
{{{x = 5}}}
5 liters of 10% acid solution are needed
check answer:
{{{.4 + .1*5 = .06*(10 + 5)}}}
{{{.4 + .5 = .06*15}}}
{{{.9 = .9}}}
OK