There's a 10 m wide, 5 m long rectangular room. In the middle of one of the longer walls, there's a mirror with width 1 m at eye level. Mikuláš is standing in front of the middle of the mirror at a distance 1 m from the mirror. What part of the room's area (in %) will he see in the mirror? Neglect the fact that part of this area won't be visible because he sees himself in front of it.
Note: when computing the area, consider only the horizontal cross-section of the room at eye level.