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

A kind heart person buy packed food at 3$/packet from United states and sells them at 1$/packet at Africa. After some time he becomes a millionaire.

How come the guy become millionaire ?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

Through your logical capabilities, can you make 7 an even?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

What am I?

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

Can you find the thief by just looking at the picture below?

What begins with T, ends with T, and has T in it?