A paper company needs to ship papre to a large printing business. The paper will be shipped in small boxes and large boxes. Each small box of paper weight 35 ponds and each large box of paper wight 60 pounds. There were 7 more small boxes shipped than large boxes and the total wight of all boxes was 815 ponds. Write a system of equations that could be used to determine the number of small boxes shipped and the number boxes shipped.