What kind of storm is always in a rush?

Find the missing letter in the last circle logically in the given below picture.

In which direction should the missing arrow point?

I know a number which is spelt in alphabetical order.
Do you?

ENEMY = 2 * LINK
LINK + 2 = HELL

Then what will be TAXI + HELL? Select from the options below:
a) ROTTEN
b) DANGER
c) HEAVEN
4) MORTAL

What goes up but never comes down?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

What is the probability of choosing the correct answer at random from the options below?

a) 1/4
b) 1/2
c) 1
d) 1/4

Sharpen your observation skills as you compare two seemingly identical images. Grab a magnifying glass, involve a buddy, and unleash your inner detective. Check the solution to see if you're a difference-detecting maestro!

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?