A coffee manufacturer 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 91 -pound burlap bags. The company has 63 bags of Colombian beans and 28 bags of Brazilian beans on hand. How many pounds of each blend should they produce in order to use all the available beans? Robust = lbs Mild = lbs