Question 19
A long rectangular room 10 m long and 2 m wide has mirrors on all four walls. Any beam of light hitting these mirrors bounces back at the same angle as shown below. A guard standing at one end of the room shines a torch at an angle of 45° to the walls, making a narrow beam that bounces off the mirrors several times, stopping when it returns to her. How many times does the beam of light bounce off the mirrors?
