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

You are in a room with no metal objects except for two iron rods. Only one of them is a magnet.
How can you identify which one is a magnet?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

Find the next number in the series below

21 32 54 87 131 ?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

A fresher was sitting in an interview. The interviewer said, "This is the last question of your interview. Tell me the accurate position of the centre of this table where your resume is kept."

How can he answer this question? What will you have answered to such a question?