Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

In a fruit store, there was a unique weighing machine that was made to weigh only cherries and strawberries as they were priced the same.

Other fruits like watermelons or mango had different machines as they were expensive.

A man successfully buys watermelons at the price of cherries. How?

Can you find out the remainder when 3^300 is divided by 5?

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Next Number in the Series,

5, 16, 49, 104, ?

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?

You need to move three matchsticks to form three squares. Can you do it?