An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

I have Rs.50 and I spend it in the way as below.

What will you call your mother's brother's brother-in-law?

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

Spot 5 differences in two Christmas tree below:

How is a fly different from a mosquito?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

What building has the most stories?