A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

If one and a half boys, eat one and a half burgers in one and a half hours.

How many burgers can 9 boys eat in 3 hours?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

Krish is 45 years old and his mother Crishtina is 73 years old.

Can you find out how many years ago, his mother was three times his age?

Can you make four (4) nines (9) equal 100?

What have one eye but still cannot see?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

A person was killed at a house party. When the police arrive, there are six people present in the house who are the friends of the victim. The name of the friends is Rohit, Aman, Nick, Gagan, and Randy.

Near the dead body, they find a few numbers written with blood by the victim on the floor. The numbers are 8, 5, 4, and 11.

The police arrests one of the friends for the murder. Whom did they arrest and why?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?