Question 860429
{{{(15u+20v)/50=16}}} and {{{u+v=50}}}.


Where those as a system come from, see the lesson, <a href="http://www.algebra.com/tutors/Mixtures%3A-All-in-Symbols.lesson?content_action=show_dev">Click on this link --- Mixing two concentrations for known amount of mixture </a>