Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

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

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?

As we know that white starts the game of chess. Can you find the scenario shown in the picture below is possible when all the white pieces are at the original place while the black pawn is not as in the below picture?