Chapter 4.1, Problem 75E

Coffee blends. A coffee company uses Colombian and Brazilian coffee beans to produce two blends, robust and mild. A pound of the robust blend requires $12$ ounces of Colombian beans and $4$ ounces of Brazilian beans. A pound of the mild blend requires $6$ ounces of Colombian beans and $10$ ounces of Brazilian beans. Coffee is shipped in $132$ -pound burlap bags. The company has $50$ bags of Colombian beans and $40$ bags of Brazilian beans on hand. How many pounds of each blend should the company produce in order to use all the available beans?