Question 162060
In words:
(gallons of stuff in 5%) + (gallons of stuff in 10%) / total mixture = 8%
Let the gallons of the 5% solution needed = {{{x}}}
{{{(.05x + .1*30) / (x + 30) = .08}}}
Multiply both sides by {{{x + 30}}}
{{{.05x + 3 = .08*(x + 30)}}}
{{{.05x + 3 = .08x + 2.4}}}
{{{.03x = .6}}}
{{{x = 20}}}gal
20 gallons of the 5% solution are needed
check answer:
{{{(.05x + .1*30) / (x + 30) = .08}}}
{{{(.05*20 + .1*30) / (20 + 30) = .08}}}
{{{(1 + 3) / 50 = .08}}}
{{{4 = .08*50}}}
{{{4 = 4}}}
OK