There are red, yellow and blue lights in a room.
The red, yellow and blue lights are all on. This is to find that the greatest common multiple of 3 and 4 in 100 is 96, that is to say, after 96 people turn on the lights, the status of the three light areas in the room will return to zero. The 97th red light is pulled 1 time, the 98th red light is pulled twice for all three lights, the 99th red light is pulled three times, and the 100 is pulled once for all three lights.