Can you spot the man between the coffee bean in the picture below ?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

Which tank will fill first?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

100 prisoners are stuck in the prison in solitary cells. The warden of the prison got bored one day and offered them a challenge. He will put one prisoner per day, selected at random (a prisoner can be selected more than once), into a special room with a light bulb and a switch which controls the bulb. No other prisoners can see or control the light bulb. The prisoner in the special room can either turn on the bulb, turn off the bulb or do nothing. On any day, the prisoners can stop this process and say "Every prisoner has been in the special room at least once". If that happens to be true, all the prisoners will be set free. If it is false, then all the prisoners will be executed. The prisoners are given some time to discuss and figure out a solution. How do they ensure they all go free?