A runner is running 5 miles per hour. how many feet is the runner running per second.

For this problem, you want to make conversions from meters to feet and hours to seconds. So, you start out with 5 miles / hour, and you divide by a unit factor of 5280 feet / miles, getting 5*5280 feet / hour. Then, you multiply by a unit factor of 1 hour / 60*60 seconds, getting 5*5280/360 feet/second. Simplify, and your final answer is

73.33.