Question of the Day #10 - 10/07/09 - Burn out

[sxty8goats]

QOTD#10 has closed 10/8/09 9:52am
You have two slow-burning fuses, each of which will burn up in exactly one hour. They are not necessarily of the same length and width as each other, nor even necessarily of uniform width, so you can't measure a half hour by noting when one fuse is half burned.

Using these two fuses, how can you measure 45 minutes?


PM answers please.

you have to light one fuse at both ends and then at the same time light the second fuse at one end. When the first fuse has completely burned up, you know that 30mins have elapsed and that the second fuse 30mins left to go. then when the first one has totally burned light the second fuse from the other end. This will cause it to burn out in 15 more minutes. then that is when 45mins have passed

[VeritasGT]

Hope I didn't screw the syntax on that one.

[sxty8goats]

nope got it just fine.

[USCGTO]

that was one long ass description...

PM Sent

[PBANDPKGTO]

Think I am in pretty quick this morning (for me anyway).

[1luckeyt/a]

pm sent. i know that i am totally late to this one.

[torrid_nc]

OK so I googled the answer, or at least an answer. I'm not sure I agree with it. When is the contest over so I can debate the answer?

[sxty8goats]

OK so I googled the answer, or at least an answer. I'm not sure I agree with it. When is the contest over so I can debate the answer?

Sometime tomorrow morning, typically @ 10AM +/- a half hour or so. Unless I'm really busy or get to work early.

FWIIW, I didn't like the answer either and actually came up with another method that I think may also work. But after thinking about it I think the 'googled' answer, if it is the one that comes up 90% of the time, is correct. :) We can argue it tomorrow, I look forward to it.

[gametech]

OK so I googled the answer, or at least an answer. I'm not sure I agree with it. When is the contest over so I can debate the answer?
I saw your post before figuring it out on my own, so I checked. I can find no flaw with the "googled" answer.
Sometime tomorrow morning, typically @ 10AM +/- a half hour or so. Unless I'm really busy or get to work early.

FWIIW, I didn't like the answer either and actually came up with another method that I think may also work. But after thinking about it I think the 'googled' answer, if it is the one that comes up 90% of the time, is correct. :) We can argue it tomorrow, I look forward to it.

Strictly thinking in terms of "time" as the riddle specifies, I don't see how any other answer could work.:dunno:

[GTOzilla]

Sometime tomorrow morning, typically @ 10AM +/- a half hour or so. Unless I'm really busy or get to work early.

FWIIW, I didn't like the answer either and actually came up with another method that I think may also work. But after thinking about it I think the 'googled' answer, if it is the one that comes up 90% of the time, is correct. :) We can argue it tomorrow, I look forward to it.

I could have googled this ?
Used my brain and came up with a decent answer. Like you already discovered there is more than one way to do this.

[sxty8goats]

I could have googled this ?
Used my brain and came up with a decent answer. Like you already discovered there is more than one way to do this.

Googling it is frowned upon and if I know you did then I would not give points for the answer. The only way for me to know would be if you admitted it. Torrid didn't submit an answer, just doesn't like the answer he got when he googled it.

Honesty wins. The only point to playing is the challenge of figuring it out. If you want to test google skills, song lyrics are much more interesting :)

[05ls7gto]

Woo I got it! Had to go back to my sophomore year Algebra II days.

[sxty8goats]

First start with both the fuses.


Light the first fuse at both ends and simultaneously,
light the second fuse at only one end.

Now, When the first fuse has burned itself out, a half hour has passed, and basically, the second fuse has another 30 minutes to go.

At this point of time ignite the 2nd fuse from the other end.

This should lead it to finish in 15 mins.

30 mins + 15 mins = 45 mins.

Light both ends of one fuse (it will burn twice as fast), and one end of the other.

The fuse with both ends lit will now burn up in half an hour. When it does, the other fuse will still have half an hour of burn time left, so if you then light the other end of the fuse still burning (burning it twice as fast), it will burn out in 15 minutes, giving you the total of 45 minutes.

I hope that makes sense

Today _ Member
10 _ VeritasGT
5 _ USCGTO
3 _ RXZKNZ
1 _ 05ls7gto
1 _ 1luckeyt/a
1 _ brada
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1 _ Ninjured
1 _ SilverGoat04
0 _ GTOzilla
0 _ PBANDPKGTO


So take Fuse # 1 and light it on both sides, the fuse will be consumed in 1/2 hr.

Take fuse # 2 and cut it in half and light one of the halfs from both side and add that burntime to the first and it be ~ 45 min
The problem with this answer is that the fuses are not uniform in length or width. You would not be able to cut the second fuse in half and know that one half burned in 30 minutes, it might be a fast or slow half. If that would work, you could have cut one fuse in half and the other in 1/4's and burned 1/2 and 1/4 fuse to time the 45 minutes.

[sxty8goats]

I'm thinking I may revise the scoring a bit. Each month the total will be zeroed, the person with the most points will go on the Honor Roll with their point total and the month/year next to their name.

Points will then be awarded as
1st = 5 points
2nd = 3 points
3rd = 2 points
all others 1 point.

Still do an occasional Two for Tuesday maybe without the bonus points. Try to bring it a little closer together but keep the game fun for everyone.

What do you all think? It is your game after all, I'm just asking the questions, you are the folk playing it. :)

[GTOzilla]

Googling it is frowned upon and if I know you did then I would not give points for the answer. The only way for me to know would be if you admitted it. Torrid didn't submit an answer, just doesn't like the answer he got when he googled it.

Honesty wins. The only point to playing is the challenge of figuring it out. If you want to test google skills, song lyrics are much more interesting :)


I agree 100% , my comment was a bit zynical ;))

[1luckeyt/a]

wow, i actually got it right.

[torrid_nc]

Since the fuse is not uniform width, I wasn't sure that you could measure 30 minutes by lighting both ends at the same time. However even if the fuse it not uniform in width, it is uniform in time. If it has burned for 30 minutes, you know it will only burn for another 30 minutes regardless of length or width.

I hate it when I think too much.