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

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?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

How many triangles can you find in this given picture?

What number comes next in the series?

5 15 5 18 5 24 14 20 _

Can you solve this picture maths equation?

How can you leave a room with two legs and return with six legs?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

A man had five children. He had $100 with him to give to his children. He decided to start with the youngest child and then give $2 more than each younger child to his next elder child.

For example, if he gives $x to the youngest child, he will give $(x+2) to the next one, $[(x+2) + 2] to the next one and so on.

Can you find out how much did the youngest one receive?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?