The executor went to the neighbouring farm and asked to borrow a sheep for a few minutes. Then he returned to the sons and said, “Half of the (now) twenty sheep is 10. A quarter of the twenty sheep is 5. A fifth of the twenty sheep is 4. 10 + 5 + 4 = 19. Then the executor took the borrowed 20th sheep back to the neighbour.
You are standing outside a closed door. On the other side of the door is a room that has three light bulbs in it. The room is completely sealed off from the outside. It has no windows and nothing can get in or out except through the door. On the outside of the room there are three light switches that control each of the respective light bulbs on the other side of the door.
Your assignment is to determine which light switch controls which light bulb. You are allowed to enter the room only once, and once you come out, you must be able to state with 100% certainty which light switch controls which light bulb.
Turn one light switch on, wait a few minutes, then turn it off and turn another light switch on. Go into the room and feel the light bulbs. The one that’s still warm is connected to the switch that you first turned on, the one that is on was the second switch you turned on, and the last bulb is controlled by the switch that you didn’t touch.
Supposedly this is given as a test in Japan. I have no idea if that’s accurate.
There are 8 people who have to cross the river on a raft.
1. Policeman
2. Thief
3. Father
4. Boy 1
5. Boy 2
6. Mother
7. Girl 1
8. Girl 2
The rules are:
Only two people can cross at a time.
Only the adults can operate the raft.
The father can’t be with the girls unless the mother is there.
The mother can’t be with the boys unless the father is there.
The thief can’t remain with anyone unless the policeman is present.
How do you get them all across?
Instead of working it out by hand, here’s a flash version.
Click on the circle to start. Click on a person to put them on the raft and click on the lever to make the raft cross.