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bonanova
Daedalian Member

 Posted: Wed Oct 01, 2008 9:44 pm    Post subject: 1 This is an old one with a twist. You have a fuse which burns at an uneven rate, but it's symmetrical about its midpoint. Starting from either end it burns completely in one hour. What is the shortest time interval it can measure?_________________ Vidi, vici, veni.
Courk
Daedalian Member

Posted: Wed Oct 01, 2008 9:52 pm    Post subject: 2

Do you have other tools available? I mean, you can do 1 second if you wanted: mark the midpoint, burn the fuse from end A for 1 second, extinguish it, measure the distance from the midpoint, and cut off the amount that burned from end B, and you now have a 1 second fuse.

 Code: A----------+----------B A...-------+----------B A...-------+-------  *snip*  ---B

zz z z z z z z z z z z z z z z z z zone-second fuse ^
bonanova
Daedalian Member

 Posted: Wed Oct 01, 2008 9:54 pm    Post subject: 3 Other tools = scissors, matches, but no stopwatch._________________ Vidi, vici, veni.
Nsof
Daedalian Member

 Posted: Wed Oct 01, 2008 10:02 pm    Post subject: 4 i get 7.5 minutes by 1) cutting in half due to symmetry we are left with two 30 minutes. 2) light one of the halves in both sides until the two burning ends meet. cut the remaining half at the same distance from the end (using the symmetry). we get two 15 minute fuses left. 3) light one of the 15m fuses on both side and the second on just one end. Turn the second fuse off when the first completely burns. we are left with a 7.5 minutes fuse._________________Will sell this place for beer
Thok*
Guest

 Posted: Thu Oct 02, 2008 12:06 am    Post subject: 5 NSOF, your 7.5 minute fuse can be turned into a 3.25 minute fuse by lighting it on both ends.
referee
June 21st, 2004 Member

 Posted: Thu Oct 02, 2008 1:59 am    Post subject: 6 You mean 3.75._________________Jan 21st, 2008: The pillaging continues. Mar 4th, 2008: Rest in Peace, Gary Gygax. May your dice always roll a natural 20 wherever you are. Be the Ultimate Ninja! Play Billy Vs. SNAKEMAN today!
Courk
Daedalian Member

Posted: Fri Oct 03, 2008 4:52 am    Post subject: 7

 Thok* wrote: NSOF, your 7.5 minute fuse can be turned into a 3.25 minute fuse by lighting it on both ends.

No, the only way you can get it to be a 7.5 minute fuse is by lighting one end of the first 15 min fuse while the second 15 min fuse is burned at both ends -- which will burn out after 7.5 minutes. If you light both ends, then both 15 min fuses will burn out at the same time.
alphatango
Daedalian Member

 Posted: Fri Oct 03, 2008 6:48 am    Post subject: 8 I think Thok's point was that once you have the 7.5 minute fuse, you could light both ends of it._________________"Hanging is too good for a man who makes puns; he should be drawn and quoted." -- Fred Allen Keeper of the Eternal Flame of the Inner Geek.
groza528
No Place Like Home

 Posted: Fri Oct 03, 2008 4:18 pm    Post subject: 9 Nsof, the fuse burns at an uneven rate, an therefore does not exhibit symmetry. Edit: Stupid me, I didn't read the original post very well. Sorry I now agree with 3.75 bonanova: I assume "zero" is not the answer you were looking for? Also, are we to assume that we only have one fuse?
bonanova
Daedalian Member

 Posted: Fri Oct 03, 2008 4:54 pm    Post subject: 10 Right on all counts._________________ Vidi, vici, veni.
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