Can you replace the question mark with the correct number in the below table sequence?

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

Which tank will fill first?

A man was convicted of a minor offence in Akbar court. Akbar decided to give him a chance. He asked him to give a statement. If the statement is true, he will be killed by lions and if it is false, he will be killed by trampling of wild elephants.

The convicted person requested help from Birbal and since the crime was not a big one, Birbal decided to help him. Whatever Birbal suggested impressed Kabir and he let the convicted person go.

What did Birbal suggest to the person?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

The centre of the third figure is empty. What digit should fit inside?

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

I have branches, but no fruit, trunk or leaves. What am I?