Question 976944
<a href="http://www.algebra.com/my/mixture-price-two-part-both-parts-unknown.lesson?content_action=show_dev">Mixture: Two-Part, price or cost, both material amounts unknown</a>
http://www.algebra.com/my/mixture-price-two-part-both-parts-unknown.lesson?content_action=show_dev



Another clever way is to assign only one unknown variable.  If p is for how much peanuts, then 70-p is how much cashews.  OR if you want EVERYTHING in variables, you might say,  M-p is how much cashews if you chose M=70.