There are four people in a house. A fireman, an athlete, an old woman and a young boy. The house catches fire. All they know is that the entire house is in flames and it will collapse exactly in thirteen minutes. Now they can move out of the house but for that, they will have to pass the staircase which is entirely heated with flames. To move, one must carry a fire extinguisher to keep the flames away. Only two people can run through that staircase at one time. But for others to go, one must return back with the fire extinguisher. The fireman is trained for such tasks and can run through the staircase in a minute. The athlete can make it in a couple of minutes. The old woman can run slowly and will cover the staircase in four minutes. The young boy will take five minutes to run through it. If all of them can make it through the staircase in specified time, all of them will be saved. When two move together, they will run with the speed of the slower one.
Can you save them and how?