Question 703854
How much salt?  v*0.07+u*0.27, where v is volume of low salt material and u is volume of high salt material.

Want result of 1180 ml. of 0.10 fraction salt solution.
{{{(0.07v+0.27u)/1180=0.10}}}
{{{v+u=1180}}}

Multiply salt equation by 100 and get
{{{(7v+27u)/1180=10}}}
Multiply both sides by 1180,
{{{7v+27u=11800}}}


Using volume equation, v=1180-u, so substitute this into the v and u equation getting us  {{{7(1180-u)+27u=11800}}}, 
..
{{{u=(1180-7*118)/2}}}
u=177 milliliters, 
so v = 1003 milliliters.