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

Replace the question mark in the picture below.

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

How is this possible?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

Below rebus represent famous DiCaprio movie. Can you name it?

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

In the given picture, in how many ways can you read the word "Tiger"?