Which number should replace the question mark?

Why do you find that most of the buildings are deprived of the 13th floor?

A man dies of old age on his 25 birthday. How is this possible?

He loves to dance, twist and prance, he shakes his tail, and as a way he sails, wingless he flies into the sky. What is he?

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

There are five men, let's say Tarun Harish Lavesh, Manoj, and Manish. All of them have a dot mark on their forehead. They can't see the dots on their forehead but can see the ones on others. The owner of WHITE Dot is an honest person and will never lie, while the owner of BLACK Dot always tells the lie.

This is the statement from Tarun Harish Lavesh and Manish:
Tarun: 'I see 3 whites and 1 black'
Harish: 'I see 4 black'
Lavesh: 'I see 3 black and 1 white'
Manish: 'I see 4 white'

What colour is the dot on each of Tarun Harish Lavesh, Manoj, and Manish's forehead?

What's the only room from which no one can enter or leave

Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

What seven-letter word has hundreds of letters in it?