Question 159481
In words:
(kg of zinc in 18% metal)+(kg of zinc in 31% metal)/(total kg of metal) = .22
Given:
Total kg of metal = {{{700}}} kg
Let kgs of 18% metal = {{{a}}}kg
Let kgs of 31% metal = {{{b}}}kg
{{{a + b = 700}}}
{{{b = 700 - a}}}
{{{(.18a + .31b) / 700 = .22}}}
{{{.18a + .31b = 154}}}
{{{.18a + .31*(700 - a) = 154}}}
{{{.18a + 217 - .31a = 154}}}
{{{-.13a = -63}}}
{{{a = 484.6}}}kg
{{{b = 700 - 484.6}}}
{{{b = 215.4}}}kg
I need 484.6 kg of the 18% metal and
215.4 kg of the 31% metal
check:
{{{(.18*484.6 + .31*215.4)/700 = .22}}}
{{{87.228 + 66.774)/700 = .22}}}
{{{154 / 700 = .22}}}
{{{.22 = .22}}}