Every day the cart is sent from village to meet barge at river dock. One day the barge arrived early, and cargo normally picked up by the cart was immediately sent toward the village by horse. The cart driver left the village at the usual time and met the rider along the way, after the rider had traveled for 8 minutes. The rider handed the load to the cart driver, who went back to his village, arriving home 24 minutes earlier than usual. How many minutes early was the barge?