Hi there! 11AM and 1PM are two hours apart, so John walked for 2 hours. To find his average speed of walking, we can basically divide both numbers, because speed = distance/time. To divide fractions, keep the first fraction the same, change division into multiplication, and flip the second fraction over. 5 1/2 as a mixed number is 11/2. 11/2 * 1/2 is 11/4 or 2 3/4 in simplest form. John walked 2 3/4 miles per hour.