Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

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?

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

In the four images below, can you find the odd one out?

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.

Which alphabet letter is a question?

A beggar on the street can make one cigarette out of every 6 cigarette butts he finds. After one whole day of searching and checking public ashtrays the beggar finds a total of 72 cigarette butts. How many cigarettes can he make and smoke from the butts he found?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

I always drive my customer away.

Who am I?

Why do we preferably have round manhole covers and not square ones?