Since 5 miles takes 40 minutes, multiplying both numbers by 2 gets you to 10 miles in 80 minutes. To get the extra 1 more miles you have to find the unit rate
5 miles in 40 minutes : divided both numbers by 5 to get 1 mile in 8 minutes add the one mile in 8 minutes to the 10 miles in 80 mins and you get 11 miles in 88 minutes
