Replace the question mark with the number below given a simple math problem.

Below, you can see three complete equations and one incomplete. Based on the three complete ones, can you complete the incomplete one?

5 $ 4 $ 3 $ 9 = 4215
6 $ 9 $ 2 $ 6 = 3816
4 $ 7 $ 3 $ 3 = 1122
7 $ 2 $ 7 $ 4 = ____

Tarang football website was hacked by one of the players. Jack, the coach of Tarang has pointed out five players as the possible hacker.
Each suspected player made three statements from each suspected player and out of which two are true and one is false.

Joseph
A) I have not hacked the website.
B) I know nothing about hacking.
C) John did it.

Hazard
A) I have not hacked the website.
B) The website was attacked by one of the players.
C) I hate Shelly

Remy
A) I have not hacked the website.
B) I have never seen Oscar in my entire life.
C) I am sure John did it.

John
A) I have not hacked the website.
B) I am sure Oscar did it.
C) Joseph was lying when he said he did it.

Oscar
A) I have not hacked the website.
B) I am sure Hazard did it.
C) I used to be friend with Remy.

So who hacked the website?

Prove that twice of ten is the same as twice of eleven.

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

There’s a one-story house in which everything is yellow. Yellow walls, yellow doors, yellow furniture. What colour are the stairs?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

What is always in front of you but can’t be seen?

If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

Solve this riddle by finding the odd one out from the rest.