A paper company needs to ship paper to a large printing business. The paper will be
 shipped in small boxes and large boxes. The volume of each small box is 6 cubic feet
 and the volume of each large box is 22 cubic feet. A total of 22 boxes of paper were
 shipped with a combined volume of 324 cubic feet. Write a system of equations that
 could be used to determine the number of small boxes shipped and the number of
 large boxes shipped. Define the variables that you use to write the system.