Another cute maths problem... (#2)

In front of you are several long fuses. (maybe we are back to launching rockets with burning fuses.. who knows...)


You know they burn for exactly one minute after you light them at one end.


But the entire fuse does not burn at a constant speed. For example, it might take five seconds to burn through half the fuse and fifty-five seconds to burn the other half.


With your lighter and using these fuses, how can you measure exactly 45 seconds of time?

I did it using magic.

Drop the barometer off the building.

Do they all burn with the same 'profile' (i.e. if half of one fuse burns in 5s the same half of the other fuses all burn the same rate) or is it random from fuse to fuse?

I know how to find 30s easily without the above restriction, but don't immediately see how that would extrapolate to 45s unless the above was true.

dhbarr said:

Drop the barometer off the building.

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I have a "rocket dropped off a building" puzzle saved up for the next one...

woferry said:

Do they all burn with the same 'profile' (i.e. if half of one fuse burns in 5s the same half of the other fuses all burn the same rate) or is it random from fuse to fuse?

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Random fuse to fuse is an appropriate way to think about it...

If you can get 30s, you are probably on the right thread...

Mushtang said:

I did it using magic.

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with a wand? It only counts if the sourced magic utilised a wand... non wand magic is illegal for the solving of cute mathematics problems, unless you have the proper paperwork.. you have your paperwork right?

RIGHT?!?!

;^)

snrkl said:

with a wand? It only counts if the sourced magic utilised a wand... non wand magic is illegal for the solving of cute mathematics problems, unless you have the proper paperwork.. you have your paperwork right?

RIGHT?!?!

;^)

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Pixie dust is also valid... If you the proper hazmat permits.

Simultaneously light the first fuse on both ends AND the second fuse at only one end. When the first fuse burns out you know 30 seconds have passed. Immediately light the other end of the second fuse and when it burns out, 45 seconds have passed (do not quibble over the practicality of igniting the second fuse's other end instantly when the first fuse burns out, or how to use ONE lighter to ignite both ends of the first fuse instantly - the truly original question didn't).

Oh, BTW, sometimes the easiest solution to a "maths" question like this, is this way:

https://tinyurl.com/y7qk6eqx

It ain't cheating when the OP used the same technique to stea...., uh, "create" the question.

Sometimes minutes seem like seconds, or vice-versa......

Posting a second reply to provide spoiler space below the first reply.


A Youtube video showing how, with the original "rope" fuses and minutes, not seconds.



[video=youtube;z7LhQrZdpIc]https://www.youtube.com/watch?v=z7LhQrZdpIc[/video]

georgegassaway said:

Simultaneously light the first fuse on both ends AND the second fuse at only one end. When the first fuse burns out you know 30 seconds have passed. Immediately light the other end of the second fuse and when it burns out, 45 seconds have passed (do not quibble over the practicality of igniting the second fuse's other end instantly when the first fuse burns out, or how to use ONE lighter to ignite both ends of the first fuse instantly - the truly original question didn't).

Oh, BTW, sometimes the easiest solution to a "maths" question like this, is this way:

https://tinyurl.com/y7qk6eqx

It ain't cheating when the OP used the same technique to stea...., uh, "create" the question.

Sometimes minutes seem like seconds, or vice-versa......

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So you decided to spoil it for all the people who aren’t in the US by posting the solution?!

Sheesh!

georgegassaway said:

It ain't cheating when the OP used the same technique to stea...., uh, "create" the question.

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So you say that when other people post something they find online they steal, but when you do it it's okay because you're just sharing information I guess? Or do you claim that you only ever post completely original content?

What I really want to know is when did math become the plural maths?

snrkl said:

So you decided to spoil it for all the people who aren’t in the US by posting the solution?!

Sheesh!

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What a kill joy,, lol..
I was just starting to get a kink in my head as I scrolled and then, bam,, spoiled,, lol...

Teddy

markkoelsch said:

What I really want to know is when did math become the plural maths?

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Outside the US, it is "maths", short for mathematics. UK influence.

I am having enough trouble with Kinematics.

snrkl said:

So you decided to spoil it for all the people who aren’t in the US by posting the solution?!

Sheesh!

Click to expand...

Mushtang said:

So you say that when other people post something they find online they steal, but when you do it it's okay because you're just sharing information I guess? Or do you claim that you only ever post completely original content?

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Geez, what a freaking attitude you both have. Well, I'm more sure in Mushtang's case he made his cracks to TROLL (I note he didn't attempt a serious answer).

Snrkl posted these things as thought they were his own, like HE thought of this math puzzle. When he simply tweaked them from ropes burning minutes to fuses burning seconds (and changing it to seconds makes it virtually impossible to do TO THE SECOND, when required to witness a "fuse" burn out , then light the other fuse in a split second with one lighter.).

He posted the question and nobody had an answer for 16 hours, from morning to near midnight. Nobody figured it out, until I did (using the same method he did for creating it). And while TRF is not a US-specific forum, about 95% or more who post here are from the same time zones as in the US. Even John DeMar didn't figure this one out.

The other thing is.... if one doesn't want to risk seeing the answer before they figured it out, then they need to stop at the first post and figure it out, since the very next post might have the entire answer.

And wow, what a "spoiler"? As though I posted who Luke Skywalker's father was or who doesn't make it to the end of the Avengers movie. It's a ripped-off brain teaser that plenty of time had passed by with nobody getting.

SHEESH!

georgegassaway said:

Even John DeMar didn't figure this one out.

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I did but I didn't want to spoil it for anyone! The spirit of these brain teasers is to ponder them, leave snrkl a pm, and he'll post a solution in a couple days. I think mine was a little different than your 'cheat'.

He never implied it was his own puzzle. He admitted he borrows them and modifies it to be more rocketry like.

georgegassaway said:

Geez, what a freaking attitude you both have. Well, I'm more sure in Mushtang's case he made his cracks to TROLL (I note he didn't attempt a serious answer).

Snrkl posted these things as thought they were his own, like HE thought of this math puzzle. When he simply tweaked them from ropes burning minutes to fuses burning seconds (and changing it to seconds makes it virtually impossible to do TO THE SECOND, when required to witness a "fuse" burn out , then light the other fuse in a split second with one lighter.).

He posted the question and nobody had an answer for 16 hours, from morning to near midnight. Nobody figured it out, until I did (using the same method he did for creating it). And while TRF is not a US-specific forum, about 95% or more who post here are from the same time zones as in the US. Even John DeMar didn't figure this one out.

The other thing is.... if one doesn't want to risk seeing the answer before they figured it out, then they need to stop at the first post and figure it out, since the very next post might have the entire answer.

And wow, what a "spoiler"? As though I posted who Luke Skywalker's father was or who doesn't make it to the end of the Avengers movie. It's a ripped-off brain teaser that plenty of time had passed by with nobody getting.

SHEESH!

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In his first maths problem thread snrkl referenced the source of the problem. He didn't take credit. Here he didn't cite the source, but didn't say he made up the problem. Not sure where you go that idea.

The idea is to let the problem linger and PM snrkl if you thought you had the answer. That way others could noodle over it for a couple days. Also explained in the problem #1 thread (but not here, which is why you may have missed that direction to not spoil it for others). That's why there were no answers for 16 hours. Enjoy our victory lap. Just don't expect much applause.

Me, I think it's funny that two threads of a math(s) problems have devolved into arguments. Strange thing to get a bee in your bonnet over, a math problem on a rocketry forum. Hee!

Well, I didn't read previous threads. This one popped up near the top of the forum list and I responded to it.

Didn't realize I was expected to search the forum for any previous threads of this nature.

So I didn't know there were any unstated "rules". I went by exactly what was (and was not) stated in THIS thread.

Guess I should have just given the answer and not said how I figured it out.

SHEESH!

georgegassaway said:

Well, I didn't read previous threads. This one popped up near the top of the forum list and I responded to it.

Didn't realize I was expected to search the forum for any previous threads of this nature.

So I didn't know there were any unstated "rules". I went by exactly what was (and was not) stated in THIS thread.

Guess I should have just given the answer and not said how I figured it out.

SHEESH!

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You're gonna have to face it, you're a party pooper. This party has been pooped.

Snrkl, what's the next problem?

It's all good.. it is all just a bit of brain teaser fun... I will be sure to have some loose guidelines to discourage party pooping (accidental or otherwise...) in the future..

Mostly because it takes the spotlight away from *me* and the big reveal with the solution! (it's only narcissism if you don't realise you're making it all about you... honest..)

;^)

@georgegassaway - thanks for contributing...

The next one will be rocket themed (well, I found a problem I can substitute a rocket into...) that will be a different kind of problem... Stat tuned and stay funky...

georgegassaway said:

Geez, what a freaking attitude you both have. Well, I'm more sure in Mushtang's case he made his cracks to TROLL (I note he didn't attempt a serious answer).

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You noted WRONG! I did, in fact, answer the question correctly... in a PM to the OP, probably a half hour or so after he posted it but within a few minutes of me seeing it.

I decided not to spoil the fun for anyone else trying to figure it out. As of right now the OP hasn't posted who PMed him the correct answer first. Unlike you I didn't have to google the answer I just came up with it on my own. I ended up adding a slightly different step after the first two, which left me with a single fuse that was 45 seconds long all by itself.

Some people here have a "short fuse".

jsdemar said:

Some people here have a "short fuse".

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Just try getting off topic on his Falcon 9 thread.

Here's a math problem. If Mary has 10 tires to the 8th power and John wears black loafers, while Sue walks to work, how many cars does it take to fill the freeway?

AfterBurners said:

Here's a math problem. If Mary has 10 tires to the 8th power and John wears black loafers, while Sue walks to work, how many cars does it take to fill the freeway?

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12 Watts per foot?

AfterBurners said:

Here's a math problem. If Mary has 10 tires to the 8th power and John wears black loafers, while Sue walks to work, how many cars does it take to fill the freeway?

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Blue, unless it’s Thursday.

AfterBurners said:

Here's a math problem. If Mary has 10 tires to the 8th power and John wears black loafers, while Sue walks to work, how many cars does it take to fill the freeway?

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Yes.