You are standing next to three switches. You know these switches belong to three bulbs in a room behind a closed door – the door is tight closed, and heavy which means that it's absolutely impossible to see if any bulb is on or not. All three switches are now in position off.
You can do whatever you want with the switches and when you are finished you open the door and go into the room. While in there you have to tell which switch belongs to which bulb.
How will you do that?
Turn on the first switch and wait for a while.
Turn off the first one and turn on the second.
Go into the room.
One bulb is shining, the second bulb is hot and the third one nothing.
What word in the English language does the following: the first two letters signify a male, the first three letters signify a female, the first four letters signify a great man, the first six letters signify a drug, while the entire world signifies a great woman. What is the word?
It was a grandeur party. In order to filter the uninvited guests, the security guard was assigned a task to check the secret password. The guests invited by the royal family also were shared with the secret password.
John wasn't an invited guest. He learned that the password is needed to make an entry. He hides himself and started watching the guests and the security.
The first guest comes. Security told him, TWELVE and the guest replied SIX. He wished him and allowed him to enter.
The second guest comes. Security told him SIX and the guest replied THREE! He was too allowed.
John made an entry as third guest. Security told him EIGHT and John replied FOUR. He was thrown out of the party!
The answer should be five. The password is not half of the digit, but the number that represents the number of digits told by security.