Yesenia and Janet are selling fruit for a school fundraiser. Customers can buy small boxes of grapefruit and large boxes of grapefruit. Jessica sold 6 small boxes of grapefruit and 5 large boxes of grapefruit for a total of $69. Janet sold 12 small boxes of grapefruit and 12 large boxes of grapefruit for a total of $156. Find the cost of each of one small box of grapefruit and one large box of grapefruit.