I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

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 ?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

How many sides does a circle have?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

What do you get if you add 2 to 100 four times?

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

In a guessing game, five friends had to guess the exact numbers of apples in a covered basket.
Friends guessed 22, 24, 29, 33, and 38, but none of the guesses was correct. The guesses were off by 1, 8, 6, 3, and 8 (in random order).

Can you determine the number of apples in a basket from this information?

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?