Question 123639
In words:
(total salt) / (total solution) = .15
Let {{{a}}} = ml of 1st solution
Let {{{b}}} = ml of 2nd solution
{{{(.25a + .05b) / (a + b) = .15}}}
Also given is
{{{a + b = 1600}}}
{{{a = 1600 - b}}}
I can substitute {{{1600}}} for {{{a + b}}} and {{{1600 - b}}} for {{{a}}}
{{{(.25(1600 - b) + .05b) / 1600 = .15}}}
{{{(400 - .25b + .05b) / 1600 = .15}}}
{{{(400 - .2b) / 1600 = .15}}}
{{{400 - .2b = .15*1600}}}
{{{.2b = 400 - 240}}}
{{{.2b = 160}}}
{{{b = 800}}}
{{{a = 1600 - b}}}
{{{a = 800}}}
800 ml of each solution should be used
check:
{{{(.25a + .05b) / (a + b) = .15}}}
{{{(.25*800 + .05*800) / 1600 = .15}}}
{{{(200 + 40) / 1600 = .15}}}
{{{.15 = .15}}}
OK