Becky and Meredith are selling wrapping paper for a school fundraiser. Customers can buy rolls of plain wrapping paper and rolls of shiny wrapping paper. Becky sold 7 rolls of plain wrapping paper and 1 roll of shiny wrapping paper for a total of $39. Meredith sold 7 rolls of plain wrapping paper and 4 rolls of shiny wrapping paper for a total of $72.

What is the cost each of one roll of plain wrapping paper and one roll of shiny wrapping paper?