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

I have teeth but i don't bite. Who Am I ?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

There was a greenhouse.
Inside the greenhouse, there is a white house.
Inside the white house, there is a red house.
Inside the red house, there are lots of babies.

What is It?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

A Shopkeeper collects 71 rupees in the form of 20 paisa and 25 paisa.
He collects a total of 324 coins.

Can you tell me how many number of 20-paisa and 25-paisa he got?

You have a basket containing ten apples. You have ten friends, who each desire an apple. You give each of your friends one apple.
Now all your friends have one apple each, yet there is an apple remaining in the basket.
How?

An apple seller is hosting a competition. He offers 1000 apples and 10 boxes to the people who pass by. The challenge is to put those 1000 apples in the 10 boxes in such a manner that if he asks for any amount of apples, the person can directly give him the boxes or a combination of boxes. If the person can do it, he promises to give a thousand apples for free.

If you happen to pass by the apple seller, will you be able to win a thousand apples?