Why did the Girl throw the butter out of the window?

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.

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

What is the last thing you take off before bed?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

What is the word or phrase below?
R | E | A | D

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

A convention is held where all the big logicians are summoned. The master places a band on everyone's forehead. Now all of them can see others bands but can't see his own. Then they are told that there are different colours of bands. All the logicians sit in circle and they are further explained that a bell will ring at regular intervals. The moment when a logician knew the colour of band on his forehead, he will leave at the next bell. If anyone leaves at the wrong bell, he will be disqualified.

The master assures the logicians that the puzzle will not be impossible for anyone of them. How will the logicians manage ?