Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

What do the following words have in common?

Assess
Banana
Dresser
Grammar
Potato
Revive
Uneven
Voodoo

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?