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

? : 3839 :: 11 : 1209

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

What has many teeth, but cannot bite?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

In the image given, you can find several triangles. Can you count them all?

What do you answer even though it never asks you questions?

Why Aeroplane windows are round?