There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

There are six people in a family namely M, N, O, P, Q and R.

R and O are brother and sister.

N is the brother of Q's husband.
P is the father of M and grandfather of R.

How many male members are in the family?

Can you solve below mathematical equation?

2^1234 - 2^1233

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

I left my campsite and hiked south for 3 miles. Then I turned east and hiked for 3 miles. I then turned north and hiked for 3 miles, at which time I came upon a bear inside my tent eating my food! What colour was the bear?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

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.