Brain Teasers
Circular Socket
Mad Ade has just purchased himself a second hand Automatic kebab rolling machine (made in Madadia, at the world famous "Botulism Bros." factory). At the back of the machine is an electrical cable with a quite strange plug. The plug has 7 prongs arranged in a circle, which matches the socket on the wall, thus allowing the plug to be rotated and inserted in 7 different ways. Each prong of the plug is numbered from 1 to 7. The holes in the socket are also numbered, but can be switched around. To make the Kebab machine work only one plug prong has to fit in the corresponding hole of the socket. How can Mad Ade Number the socket holes in such a manner that no matter how the plug is inserted, at least one prong will fit into the correctly numbered hole in the socket?
Answer
The prongs on the plug are already marked with consecutive numbers: 1, 2, 3, 4, 5, 6, 7. Number the holes in the socket clockwise, with every other number, then wrapping back around: 1, 3, 5, 7, 2, 4, 6. This ensures at least one correct connection no matter how the plug is inserted.Hide Answer Show Answer
What Next?
View a Similar Brain Teaser...
If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own.
Solve a Puzzle
Comments hidden to avoid spoilers.
Follow Braingle!