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.

A spy was in Canada trying to steal insider information on how to set up new Maple Syrup factories in their country. He was introduced to the operations manager of the biggest factory in Canada. However, the manager was suspicious and decided to test him with a question before he trusted him. So he asked, “What would you be sure to find in the middle of Toronto?” The spy thought fast and came up with an answer for the manager. What was his answer?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

I organized a small get together at my home.
In the party , i have a barrel with some whiskey in it.

Suddenly Guest 1 say 'I bet this barrel of whiskey is more than half full'.
'No, it's less than half full' Guest 2 replied.

I don't have any measuring instrument and without removing whiskey from it , how can i determine which of the guest is right ?

Sherlock Holmes was challenged to make a pre-drawn line smaller without erasing it. He did it in fractions of seconds. How?

Which wheel of car does not rotate when you turn your car right?

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

What occurs twice in a week, once in a year but never in a day?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?