Bill’s Coffee House, a store that specializes in coffee, has available 75 pounds (lb) of A grade coffee and 120 lb of B grade coffee. These will be blended into 1-lb packages as follows: An economy blend that contains 4 ounces (oz) of A grade coffee and 12 oz of B grade coffee and a superior blend that contains 8 oz of A grade coffee and 8 oz of B grade coffee. 

(a) Using x to denote the number of packages of the economy blend and y to denote the number of packages of the superior blend, write a system of linear inequalities that describes the possible number of packages of each kind of blend. 

(b) Graph the system and label the corner points.