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

How many words can a pen with half refill write?

What part of the chicken has the most feathers?

When can we add 2 to 11 and get 1 as the correct answer?

A bank customer had $100 in his account. He then made 6 withdrawals. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
$50 $50
$25 $25
$10 $15
$8 $7
$5 $2
$2 $0
----- -----
$100 $99

Why are the Totals not tallying?

I cannot talk, but I always reply when spoken to. What am I?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

A boy was locked in a room by some robbers. All that is in the room is a piano, a calendar, and a bed. The room is locked from the outside. What does he eat, drink, and how does he escape and get out?

How can a man go eight days without sleep?

You are stuck on an island where you have nothing. You find four pieces of paper somewhere on the island. What will be your strategy to escape from the island safely?

PS: No other resource is available to you on the island, neither can you build anything.