If you say my name, I will no longer exist. What am I?

The more of this there is, the less you see. What is it?

Two friends were betting. One said to the other, "The coin will be flipped twenty times and each time the coin lands on the head, I will give you $2 and each time it lands on the tale, you will give me $3." After flipping the coin twenty times not a single penny was exchanged among them.

How many times did the coin land on heads?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

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

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

Find the number of squares in the below picture

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

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