Why is the longest human nose just 11 inches?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

Can you place six X (crosses) in below board without making three in a row in any way ?

How do you go from 98 to 720 using just one letter?

In a stable, there are men and horses. In all, there are 22 heads and 72 feet. How many men and how many horses are in the stable

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth, the other always lies and you don't know which is which.
What is the question you ask?

Pronounced as 1 letter, And written with 3, 2 letters there are, and 2 only in me. I’m double, I’m single, I’m black blue and grey, I’m read from both ends, and the same either way. What am I?

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

The dirtier I get, the whiter I look. Who am I?