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

Find the missing number in the sequence below:

You order chicken wings at KFC in the boxes of 6, 9 and 20. What is the largest number of wings that you cannot obtain by buying in any combination of the boxes?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

John asked Jack, "The time right now is 7 pm. Can you tell me what will be the time 23, 999, 995 hours later ?"

While Bella does not know the answer, do you ?

How can one talk without saying a single word?

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.

Can you count the number of matches in the picture below ?

Can you name four days which start with the letter 'T'?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?