If it took eight men ten hours to build a wall, how long would it take four men to build it?

What is the centre of gravity?

who is silent in the parliament?

What you cannot hold but it is yours?

Before Mount Everest was discovered, what was the highest mountain in the world?

A person is found murdered in his Chamber. When the crime scene is investigated, the Investigator find out that there is a calendar on which the victim has written a few numbers with his blood. The numbers are 4, 11, 11 and 4.

There are four suspects in the murder, John, Jacob, Anna and Lee. Can you find out who is the murderer?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

A lion and its tamer are standing inside a cage that measures 1 unit in radius. Both of them can effortlessly run at the speed of 1 unit maximum.

1) Suppose the lion is hungry, will he be able to eat up the tamer?
2) If yes, how long can the tamer survive?

A bomb exploded in a room full of married couples and no one died. How?