Also he can levitate so he doesn’t need stairs.
3 Likes
Ftfy
3 Likes
I misread it to the exact same way, so don’t feel bad.
3 Likes
144 responses.Just put a VFD on one and set it for 30 Hrtz (yes a VFD can run a single phase motor).
3 Likes
Exactly . . . My local Volunteer Fire Dept. is awesome 
2 Likes
If the building has a meter room in the basement or ground level then all he has to do is walk to the top and turn off everything in each apartment except the fans.
Go back to the basement, turn on one fan and see which meter starts ticking. Repeat for the others.
7 Likes
Lazy electrician? Sure, that means as little time spent there as possible and as little effort, too. To make this harder, maybe the person that wired it initially swapped hot and neutral anywhere between the fan and the basement switch on any given fan, so there goes continuity and voltage sniffers/indicators…and maybe they’re all on the same breaker so you can’t even short one and sniff for a hot upstairs or use a circuit finder, and to make it even harder maybe only the hot goes into the box and through the switch (no neutral) and the box isn’t even grounded. Oh, and to make it even more difficult you don’t even feel like carrying test equipment or tools or a ladder, nothing outside of what can fit in one hand.
1: Get yourself a cup of water, a screwdriver, a wirenut and a couple five foot lengths of 14 gauge wire from the truck.
2.In basement turn all switches off then: A switch turned off (control group for off), B switch turned on (control group for on), C switch is turned off and unscrewed from switchbox, load-side wire is removed and a 5’ length of the 14 ga is attached and put into a cup of tap water on the ground, the other 5’ wire is screwed in its place on the switch and also put into the tap water, switch is turned back on.
2: Trudge upstairs and off fan is A, fastest fan is B and “dimmed” fan is C.
- Go downstairs and hook it all back together.
3 Likes
If @cubby hadn’t already mentioned it, I would have.
2 Likes
Totally- it’s not quite the same, though, so it’s not as simple. (Laaaammmme.) There’s a necessary hour between shutoff and feeling for heat, and there are three separate fans instead of one lightbulb. They absolutely based it off the lightbulb problem but added a part and tweaked it just right to make it a pain.
2 Likes
Turn two switches on, and one switch off. Climb the stairs. Pull out your cellphone and set up a livestream to youtube of one of the fans that’s running. Leave a note on the dining room table asking the tenant to bring the phone back to you. Go back down to the basement, and figure out which switch controls the fan that’s being livestreamed.
Never really got these puzzles. You have to cheat somehow. Why not that way? Hmm?
3 Likes
A much better outcome, in my opinion
Dust accumulating on the fan. Won’t be disturbed on the fan that never was on.
He walks up and attaches a piece of string to a blade on each fan, at the end of the string he attaches a big piece of card with the flat number on, he places that in a window that can be seem from the ground.
Goes back down - turns on one and looks at the windows to see which card has been removed from the window. Repeat for the second and then logic dictates the third.
This seems a much lazier way than rewiring anything…
10 Likes
I think that switch on fan A at the start and only right before the electrician walks up, switch on fan B and leave fan c switched off. The coolest room will be fan A, the remaining one fan that is switched on will be fan B and the last fan that is not switched on I’ll be fan C.
On a side track, who still uses fans in the summer? 
Install an Wei Wei Aircon system in your room instead to cool down your room. Haha. Change all the fans to an aircon, fired the electrician. Problem solved.
1 Like
Except fans don’t cool rooms. They just circulate air, which feels like cooling as it evaporates sweat.
1 Like
Yep. Using one right now. 
Nope. Windmills Fans do not work that way.
2 Likes
Any fluid, gas or liquid, passed rapidly over a surface, will transfer heat energy. If the room’s warmer than the greater environment, it will cool it.
1 Like
All of these “it’s so close to the lighbulb puzzle” answers are so close! It IS the lightbulb puzzle. This is how he does it.
Starting in the basement:
step 1: turn on switch A
step 2: remove switch B and replace it with a light bulb
Now go up the stairs:
step 3: find the room with the spinning fan. that’s connected to swich A
step 4: go to either of the other rooms and spin the fan by hand vigorously for five minutes (motors are also generators!)
Back down the stairs (still only one climb up):
step 5: touch the lightbulb wired in place of switch B. Is it warm? then switch B controls the fan that was spun by hand in step 4. Is it not warm? Then switch B is connected to the fan in the other room.
step 6: remove the lightbulb and replace the switch.
3 Likes
The stairclimb is an hour long. If you can tell a lightbulb is still warm from hand-spinning a fan an hour after the fact, I’d be surprised. I’m sure the person who wrote this puzzle had some solution in mind when they put the hour-long delay in.
I know you have a solution that would really work in real life. My problem is with puzzles that are set up like this, where there is typically one thing we are supposed to think about about real life that gives the “right” answer and any other real-life thing we think of is dismissed as cheating. So while your solution is a good one, it might be “wrong”, and we have no way of knowing other then asking the person who offered the puzzle what answer they are looking for.
3 Likes
Burn down the entire building. Now there are no fans and no switches so the issue is moot.
9 Likes
