Complete the table series riddle by finding the number that can replace "??".

What demands an answer, but asks no questions

Joseph organises an exotic office New year party at the beach to his important fellow employees.

Following are the important people that will come to the party

1. Joseph

2. Joseph 2 girlfriends- Carol Vanstone and Tracey Hughes

3. The sales head Clay Vanstone.

4. Clay Vanstone 2 associates.

5. Mr. Jeremy and his Secret Tab.

They all need to cross a small river to reach the beach, however, Joseph has got just one boat.

There are few rules for crossing the river.

1. The capacity of the boat is limited to just two people.

2. Clay Vanstone associates will not stay with Joseph without Clay Vanstone.

3. Carol Vanstone and Tracey Hughes will not stay with the Clay Vanstone without Joseph.

4. Mr. Jeremy would never leave the Secret Tab alone.

5. Secret Tab counts as a person.

6. Only Joseph, Clay Vanstone or Mr. Jeremy can drive the boat.

7. The two girlfriends Carol Vanstone and Tracey Hughes will not stay with the Clay Vanstone without Joseph.

8. No Associates would stay with Joseph without their Clay Vanstone.

9. Mr.Jeremy will not leave the Secret Tab alone.

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

On my way to St. Ives I saw a man with 7 wives. Each wife had 7 sacks. Each sack had 7 cats. Each cat had 7 kittens. Kittens, cats, sacks, wives. How many were going to St. Ives?

A man walked into a pub and went straight towards the Barman. He asked for a dirty martini from the Barman. The Barman thought something and then pulled out a pistol from his drawer and aimed it directly at the man. Why did he do that?

A murder has been committed in a house. You are a detective and have to find out the murderer.

You investigate by asking three questions to each of the six suspects. Out of those six suspects, four are liars. It is not necessary that they speak everything a lie. But in their answers, there must be at least one lie. One of the six is the murderer.

There are eight rooms in the house in which the murder has been committed: Kitchen, Living Room, Bathroom, Garage, Basement, 3 Bedrooms.

At the time of the murder, only the murderer was present in the killing room. Any number of people can be present in any of the other rooms at the same time.

Can you identify the murderer and the four liars? Also, can you find out who was in which room?

The responses of all the suspects are mentioned below.

Joseph:
Peter was in the 2nd bedroom.
So was I.
David was in the bathroom.

Mandy:
I agree with Joseph that David was in the bathroom and Peter was in the 2nd bedroom.
But I think that Joseph was in the living room, OH MY GOD!

Peter:
Mandy was in the kitchen with Christopher.
But I was in the bathroom.

David:
I still say Peter was in the 2nd bedroom and Jennifer was in the bathroom.
Joseph was in the 1st bedroom.

Jennifer:
Peter was in the bathroom with Christopher.
And Mandy was in the kitchen.

Christopher:
David was in the kitchen.
And I was in the 2nd bedroom with Peter.

PS: The corpse was found in the Living Room.

A crime was committed at baker street. Ibrahim Dakota who was shot in the stomach was the main suspect. Sherlock questioned the suspect. The conversation started as:
Sherlock: What's your story, Ibrahim?
Ibrahim: I was walking around baker street and suddenly a man from the back shot me. I ran as fast as I could to save my life".
Sherlock: That is enough (and ask the police to arrest him).

Why does Sherlock think he is the murderer?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

If an electric train is travelling south, then which way is the smoke going?