If you toss a coin 10 times and it lands heads up every time, what are the chances it will land heads up if you toss it again?

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.

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Kareena is older than Katrina and younger than Karishma. Isabelle is younger than Bipasha and Karishma. Bipasha is older than Karishma. If Kareena and Isabelle are the same age, who's the youngest?

After a heavy Thanksgiving meal, the night watchman went to work. In the morning, he told his boss he had dreamed that a saboteur planted a bomb in the factory and that he felt it was a warning. The boss promptly fired him. Worker confused, Why boss fire him?