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?

Can you place six X (crosses) in below board without making three in a row in any way ?

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

How can you tell a raw egg from a hard-boiled egg?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?