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

What does below rebus means ?

A man is sitting in a pub feeling rather poor. He sees that the man next to him is extremely rich. He turns to the rich man and says to him, 'I have an amazing talent; I know almost every song that has ever existed.'
The rich man laughs.
The poor man says, 'I am willing to bet you all the money you have in your wallet that I can sing a genuine song with a lady's name of your choice in it.'
The rich man laughs again and says, 'OK, how about my daughter's name, Joanna Armstrong-Miller?'
The rich man goes home poor. The poor man goes home rich.

What song did he sing? A man is sitting in a pub feeling rather poor. He sees the man next to him pull a wad of £50 notes out of his wallet. He turns to the rich man and says to him, 'I have an amazing talent; I know almost every song that has ever existed.' The rich man laughs. The poor man says, 'I am willing to bet you all the money you have in your wallet that I can sing a genuine song with a lady's name of your choice in it.' The rich man laughs again and says, 'OK, how about my daughter's name, Joanna Armstrong-Miller?' The rich man goes home poor. The poor man goes home rich. What song did he sing?

Imagine you are in a room with no windows or doors. How will you get out?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

Which country gets ill every time?

What part of the chicken has the most feathers?

Which city is three-fifths chick two third cat and 50% goat?

What do you call a fish without an eye?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.