Since an average person works 40 hours a week an FBI agent will work more because when you work a job while dealing with criminals cases can come at any time and at any minuute. Plus, there are so many cases you will always be busy!
Real Estate Agents work for themselves, so it is really up to them to decide what days they work. Many agents work seven days a week if they need to. They work whenever they must in order to make a sale, especially with the market so depressed in many areas.