Est. 1998 — 27 years of woodworking knowledge
fuse timer
You are given two lengths of fuse, both of which are known to burn for 30 seconds. However, due to manufacturing variances, the burn rate is not constant. E.g., one fuse might be 4 feet long, and will burn only 1 foot in the first 20 seconds, and three feet in the remaining 10 seconds.
Assuming no delays in lighting the fuses, how can you use these two fuses to time 45 seconds?
[credit goes to CarTalk for this one]
Re: fuse timer
Either fuse first. Burn one fuse and that equals 30 seconds.
Immediately light both ends of the second fuse at he same time and it will burn for 15 seconds. This came to mind almost immediately which leads me to think that somewhere down the line I did/heard this puzzle before
I didn't notice the time of the placement.
I apologize. I'm off to the box. Sorry.
:-)
You can come out now. It was probably too easy anyway!