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

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

I organized a small get together at my home.
In the party , i have a barrel with some whiskey in it.

Suddenly Guest 1 say 'I bet this barrel of whiskey is more than half full'.
'No, it's less than half full' Guest 2 replied.

I don't have any measuring instrument and without removing whiskey from it , how can i determine which of the guest is right ?

Can you find the key in the picture below?

Can you name four days which start with the letter 'T'?

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?

what does this below rebus represent identXQQQQQME

It has five wheels, though often think four, You cannot use it without that one more, You can put things in it, you can strap things on top, You can't find it in the market, but you can still go shop. What is it?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?