A conundrum

sandtrekker

sandtrekker

I was listening to a book programme on National Public Radio in San Francisco yesterday and one of the guests was commenting on a conundrum he read in a recent novel by Nelson DeMille, I believe.

"If you do nothing how do you know when you have finished?"

I am still trying to answer this and probably never will. Geoff/R

Bud

I finished doing nothing about a year ago. I knew I had finished when I started doing something. Conundrum solved.

New conundrum: Three light switches outside a closed room, corresponding to three lightbulbs inside the room. You may flip the switches on and off as many times as you please, but you may only enter the room once. How do you find out wihich switch corresponds to which bulb, given that you can't hold the door open and flip the switches at the same time?

Carol

Presumably when you die.

Jan

Now, is this where you leave one switch on time enough for one light bulb to warm? Turn that switch off and another on then enter the room.

Illuminated bulb corresponds to on switch.
Warm bulb matches previously activated switch.
Cold bulb must be operated by switch not touched.

Flick

Now isn't that interesting. The man - Jan comes up with the logical explanation, carefully thought out and the woman, Nenastew bypasses all that and points out a flaw in the original question. 

Carol

neither could I. I'd have gone with the being able to see into the room some other way.

Betsie

Could there be another person in the room who shouts through the keyhole when you flick a switch. Nah, guess not.

Bud

Sorry Flick, for forgetting to mention that it wasn't a glass door. I also should have mentioned that you're not allowed telepathic powers, that the lightbulbs don't sing different tunes when you switch them on, and that you're not allowed to run and get a spade and dig under the wall to avoid opening the door. I really must put more thought into these questions. ;)

Jan is correct. Well done Jan!