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

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

Today is a very icy and cold morning in Newcastle. Mr Shearer, an office bus driver arrived to pick up the employees from the last stop. Shearer suddenly remembers that he needs to pick a newly joined 4miles to the north. Mr Shearer lost his direction compass, a few minutes later Shearer is able to figure that he is moving in the correct direction i.e. north. How did Shearer know that he is moving in the correct direction?

I cannot talk, but I always reply when spoken to. What am I?

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 = ____

Why do people go to bed?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

Find the 8 in the below-given Image.

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Replace the question mark with the correct number.