Why Wine Glass Stem is so long?

Move four matchsticks to the below square to form three squares?

If eleven plus two equals one, what does nine plus five equal?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

10+10 and 11+11 can give you the same answer.

Explain how?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

Katniss and Peeta are liars. They both lie on some specific days.

Katniss lies on Fridays, Saturdays and Sundays. She speaks the truth on all other days.

Peeta lies on Tuesdays, Wednesdays and Thursdays. He speaks the truth on all other days.

Can you tell that one day of the week when both of them will say "Tomorrow, I will lie."?

Can you name four days which start with the letter 'T'?