What is always in front of you but can’t be seen?

What does Alexander the Great and Winnie the Pooh have in common?

You are given 16 witch hats. The hats are divided in four different colours – red, blue, green and yellow. Every colour has been assigned to four hats. Now each of the hat will be glued with a label of an arithmetic sign – ‘+’, ‘-‘, ‘x’ or ‘/’. But you can label one sign only once on one colour. In such an arrangement, the hats can be uniquely defined by its colour and symbol.

Can you arrange all the 16 hats in a 4x4 grid in a fashion that no two rows and columns have a repetition of colour or sign?
We have arranged four hats in the below picture to assist you.

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?

Can you place three balls such that the equation shown in the picture holds true?

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?

Find the next number in the series below.

6 18 270 72090 ?

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?

If you say my name, I will no longer exist. What am I?