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

You walk into a room where there are three primates held in their respective cages:
1) A lion who is eating the flesh of a goat.
2) An orangutan who is playing with blocks.
3) A donkey who is sitting idle.

Who is the most intelligent primate in the room?

Why is it very easy to weigh a fish?

Who is that with a neck and no head, two arms and no hands? What is it?

What always comes into a house through the keyhole?

In the following series, a set of numbers is progressing with a particular pattern. Can you deduce that pattern and find the missing set?

(2 + 6), (21 + 6), (58 + 6), (119 + 6), ___

When does a USA Potato change its nationality?

What brings you down but never up?

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?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.