Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

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 _

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Can it be possible to build a house that has all its four walls facing towards the South?

Count the number of squares in the picture below.

Why is the Hole below a Lock?

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches

I inserted a coin in a bottle and closed its mouth with the help of a cork. Now, I was able to take the coin out from the bottle without taking out the cork or breaking the bottle. Can you tell me how I did it?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

During which month do people sleep the least?