Here's this week's Friday Puzzle, from my friend and occasional podcast partner Paul Wright. First, the answer to last week's puzzle:
Yesterday my mother asked me to buy some stamps. Stamps, in the land of BrainBashers, are available in 2p, 7p, 10p, 15p and 20p denominations. For three types of stamp I was asked to buy five of each. For the other two types of stamp, I was asked to buy six of each. Unfortunately I forgot which I was supposed to buy five of and which to buy six of. Luckily my mother had given me the exact money required to buy the stamps, £3.00 and the shopkeeper was able to give me the correct stamps. Which stamps did I buy?
The answer is: Five lots of 2p, 7p and 15p and six lots of 10p and 20p. The shopkeeper rightly figured that I required five lots of each of the stamps, which came to £2.70, he also knew I required two more stamps which added up to the difference. QED.
Here's this week's puzzle, from Brainbashers, which is something of a classic, I'm sure you'll agree:
There is a closed room with a light in it. Outside, there are 3 light switches. You can flick any of the switches any number of times. You can only open the door and go into the room once. You know that the light is initially off. How can you determine which light switch operates the light?
Other links:
— This is the title of a typical incendiary blog post
— LOST: Flight 815 Crash in Real Time
— Jean Michel Jarre: King of Laser Quest
— Autonomous VTOL unmanned air vehicle
— Crosswind Landings around the world
— VVVVVV
