Amy and Cody are selling wrapping paper for a school fundraiser. Customers can buy rolls of plain wrapping paper and rolls of shiny wrapping paper. Amy sold 12 rolls of plain wrapping paper and 4 rolls of shiny wrapping paper for a total of $72. Cody sold 10 rolls of plain wrapping paper and 12 rolls of shiny wrapping paper for a total of $112. Find the cost each of one roll of plain wrapping paper and one roll of shiny wrapping paper.