Question 908519
Very common type of mixture problem.  This lesson discusses and solves this type in general:


<a href="http://www.algebra.com/my/Mixtures%3A-All-in-Symbols.lesson?content_action=show_dev">http://www.algebra.com/my/Mixtures%3A-All-in-Symbols.lesson?content_action=show_dev</a>


(Apparently I must say again, that the lesson DISCUSSES AND SOLVES the problem in general.  I have answered too many of this type of problem, and I rarely do so in full anymore; instead I created the lesson so a student can learn and understand.  THE SOLUTION PROCESS AND FORMULA IS IN THE LESSON!)