What is always in front of you but can’t be seen?

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

The cream is heavier than Milk. True or False?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

With the help clues provided in the image, can you find the 5 digit key?

You need to remove two matchsticks to make the below equation true. Can you do it ?

What is the centre of gravity?

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet?

You know three triplets: Frank John and Wayne (need to return your money). Frank always tells the truth while John and Wayne always lie. You meet one of them on the road and can ask him a three-word question.
Which question, will you ask?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?