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

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

A bomb exploded in a room full of married couples and no one died. How?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?

John is selling fruits.
He sells grapes at $30, Dates $25, and a Wolfberry $45.
At what price does he sell fig?

PS: Logical Thinking

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

It belongs to you, but other people use it more than you do. What is it?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

A lion and its tamer are standing inside a cage that measures 1 unit in radius. Both of them can effortlessly run at the speed of 1 unit maximum.

1) Suppose the lion is hungry, will he be able to eat up the tamer?
2) If yes, how long can the tamer survive?