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?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

Mr Black, Mr Gray, and Mr White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr Black, who hits his shot 1/3 of the time, gets to shoot first. Mr Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. If you are Mr Black, where should you shoot first for the highest chance of survival?

What will you call your mother's brother's brother-in-law?

Replace the question mark with the number below given a simple math problem.

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

A very interesting trivia question for all.

Why do men's shirts have their buttons on the right side and women's have buttons on the left-hand side?

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

I look at you, you look at me, I raise my right, you raise your left. What am I?