What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

We have four gears with below features=> Both Gear A and D has 60 teeth=> Gear B has 40 teeth=> Gear C has 20 teeth=> Every two minutes, Gear B makes 25 full turns.What is the relative speed of Gear A and Gear B?

In a university, a professor gave a set of three problems to the three brilliant students of his class. See the image for the questions.

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

Can you Find and name the hidden bird in the picture below ?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

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?

A newspaper is supposed to have 60 pages, but pages 24 and 41 are missing.
Which other pages won't be there?

Why is the Hole below a Lock?

what does the below rebus mean?