Answer:
He can run 7 miles in 1 hour
Explanation:
Let's find how much he can run in 1/4 hour. To do this we divide 5 1/4 by 3
5 1/4 miles divided by 3 = 7/4 miles
He can run 7/4 miles in 1/4 hour
Since 1 hour is 1/4 hour * 4 we can multiply 7/4*4 to get how far he can run in an hour.
7/4*4=7 miles