Coffee Mix
Playing around GeoGebraTube I came across this nice visualization of the coffee problem by Judah Schwartz.
http://www.geogebratube.org/student/m243091
And it made me want to do a visualization of the problem.
This sketch allows you to make a mix, and guess what the price should be.
You might also try to make a mix to hit a certain price point.
Can different mixes have the same price/pound?