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

What has 13 hearts but no other organs?

What country can make you shiver?

What breaks yet never falls, and what falls yet never breaks?

How is a fly different from a mosquito?

Take away my first letter, then take away my second letter. Then take away the rest of my letters, yet I remain the same. What am I?

In order to complete the racing competition, the Mexico racetrack has to submit its top and the most famous three horses to win the competition. Due to an electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the Mexico racetrack. But there can be only five horses at a time on the track. What will the least number of races that can be conducted to find out the three fastest horses?

You are in a room with no metal objects except for two iron rods. Only one of them is a magnet.
How can you identify which one is a magnet?

You see me once in June, twice in November, and not at all in May. What am I?

I am sure no one can have two things for dinner. what are they?