What number when divided in half becomes zero?

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

What two things can you never eat for breakfast?

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

What is common among 11, 69, and 88?

How is the moon similar to a dollar?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.