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

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

There are three Athletes (John, Tarun and Harish) and their individual Coaches (Jacob, Meenaxi and Priyanka) standing on the shore.
No Coach trusts their Athlete to be near any other Coach unless they are also with them.
There is a boat that can hold a maximum of two persons.
How can the six people get across the river?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

The Judge knows that Alamgir was killed by his girlfriend Jasline, but the judge is unsure whether to punish her. Why?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

How many letters are in the alphabet?

In which direction should the missing arrow point?