When can we add 2 to 11 and get 1 as the correct answer?

What is the centre of gravity?

In the image below, you can see two glasses and two matchsticks.You need to move four matchsticks in such a manner that the crosses come inside the glasses. Note: you cannot move the crossed.

What has one eye, but can’t see?

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

If you had an infinite supply of water and 5-quart and 3-quart pails, how would you measure exactly 4 quarts? What is the least number of steps you need?

What is the next number in this series?

4,12,84,3612....

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

On a bus, there is a 26-year-old pregnant lady.
A 30-year-old policeman.
A 52-year-old random woman.
And the 65-year-old driver.

Who is the youngest?