Question

The Standard blend of coffee uses 4 oz arabica beans and 12 oz of robusta beans per package; the Deluxe blend uses 10 oz of arabica beans and 6 oz of robusta beans per package. The merchant has 80 lbs. of arabica beans and 90 lbs. of robusta beans available. Find a system of inequalities that describes the possible number of Standard and Deluxe packages the merchant can make.