Since he traveled 3 miles during the 3rd hour, that means he traveled 9 during the other 2. The most he can ride during the 1st hour is 5 miles that would leave 4 miles for the second hour. IF he traveled less than 5 miles during the 1st hour he would need to travel more than 4 miles during the second hour. Therefore the fewest miles he could have traveled during the second hour is 4