What is the centre of gravity?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

What 5-letter word typed in all capital letters can be read the same upside down?

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

What is both possible and impossible at the same time?

What always comes into a house through the keyhole?

As shown in the picture below, we can see a boy hanging on the tree branch to save his life. There are various ways in which he can die like1. A snake hanging toward the right waiting to bite the boy.2. A roaring Lion near the tree.3. Two crocodiles are ready to attack if the boy reaches near water. The tree is chopped to some extent, so can fall as if he moves a lot. Can you give this boy an escape plan?

What does below rebus means ?

Solve the riddle below:

If a Chicken says, 'All chickens are liars" is the chicken telling the truth?

10+10 and 11+11 can give you the same answer.

Explain how?