1 A trucker drove 9 hours to deliver a shipment of lumber Returning home with a lighter load, the trucker averaged 8 miles per hour faster than on the earlier journey. After 7 hours, the trucker was only 60 miles from the starting point. The equation 0n 9s=7(s+8)+60 models the situation , where s represents the speed traveling to the delivery site . What is the value of s, in miles per hour?