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

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

I am white when I am dirty, and black when I am clean. What am I?

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

John is asked to stand behind Jacob and Jacob is asked to stand behind John. Both of them feel confused about it and don't know what to do?

But it is quite possible, do you know how?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

Can you Find and name the hidden bird in the picture below ?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?