You have a set of 3 light switches outside a closed door. One of them controls the incandescent light bulb inside the room. With the door closed from outside the room, you can turn the light switches on or off as many times as you would like.

You can go into the room – one time only – to see the light. You cannot see whether the light is on or off from outside the room, nor can you change the light switches while inside the room.

No one else is in the room to help you. The room has no windows.

Based on the information above, how would you determine which of the three light switches controls the light inside the room?

A guy claims to do the following thing. He puts a coin in a glass bottle. Then, he shuts the mouth of the bottle with the help of a cork. Now he manages to remove the coin out from the bottle without taking out the cork or breaking the glass bottle.

Do you know how he can do it?

Given 1000 bottles of juice, one of them contains poison and tastes bitter. How do you find it in the smallest number of sips? Adding a single drop of poison to the juice will make it taste bitter. You can assume that you have the antidote for the poison.