The average speed would be 53 miles per hour, hope this helped, if you need me to explain then here is the way, so all you do is divide 265 by 5 and what I did to help make it faster was split 265 into 250 and 15 so 250 divided by 5 is 50 and 15 divided by 5 is 3 so 50 + 3 = 53!