Lenny Conundrum 149

[sirclucky]

W00t for having powerful math software on my computer. I couldve solved it by hand, but it sure saved alot of time ;-).

And whats with answers being fractions? All my letters stood for whole numbers

[kc_6201]

Sirclucky, what is this "powerful math software" you speak of?

[Mkali]

*has a headache*

*looks at this weeks LC*

*has a worse headache*


Since there's no headache emoticon I'll stick with this to show my frustration *waddles to the sidelines* darn you maths

[WockyChocky]

It's not the linear algebra that's throwing me, but the dozen or so unknown variables.

Linear algebra is the dozen or so unknown variables in those equations. And that statement, after nearly 30 years since I took Linear Algebra, is the first time I have used anything I learned in that course. It would have been the 2nd time (after solving the LC), but I forgot how to do it.

[Officer 1BDI]

I'll rephrase: fewer variables = much easier (for me) to solve.

[kc_6201]

Well that took a while, but it wasn't actually as difficult as I thought it would be, IF you use multiple equations from other people. At one point I copied an equation wrong so I got fractions for c and d and kept going on to solve n and m...but then I plugged m into a bunch of equations to check and they didn't work out so luckily I caught it.

I don't want to submit my answer yet until I check with someone who also thinks they have solved it.

[sid_basu4243]

Not since my undergrad days have I tried to invert a 13x13 matrix without a computer math software, but somehow I succeeded using Excel. Also I realised that I can write a matrix inversion program using Excel, have not seen that before, so that was definitely worth spending an hour and half of my life..

Just to let you all know that not everyone has the same set of numbers - but the answers will be the same.

This cannot happen - the set of numbers are unique. If I be a little bit techie here, this is because the underlying matrix is non-singular (in maths term). Or in other words you cannot have one of the equation derived from a combination of any other equations, so 13 equations and 13 variables will lead you to unique set of answers.

I agree with neomanias answer, but as Murphys law says that if LC is out always during daytime (in HI) whenever they have maths questions, or something similar, (except when LC is a hybrid of Maths and non-Maths like that sudoku and Xweetok thing couple of weeks ago) I am going to miss the avi again.

[endeavourl]

Not since my undergrad days have I tried to invert a 13x13 matrix without a computer math software, but somehow I succeeded using Excel. Also I realised that I can write a matrix inversion program using Excel, have not seen that before, so that was definitely worth spending an hour and half of my life..

Just to let you all know that not everyone has the same set of numbers - but the answers will be the same.

This cannot happen - the set of numbers are unique. If I be a little bit techie here, this is because the underlying matrix is non-singular (in maths term). Or in other words you cannot have one of the equation derived from a combination of any other equations, so 13 equations and 13 variables will lead you to unique set of answers.

I agree with neomanias answer, but as Murphys law says that if LC is out always during daytime (in HI) whenever they have maths questions, or something similar, (except when LC is a hybrid of Maths and non-Maths like that sudoku and Xweetok thing couple of weeks ago) I am going to miss the avi again.

This makes me feel a little better (i hope your right). I did not get the same answer as neomania, and I thought I had added wrong there, but when I went back to recheck, I still had my old answer.

[background_noise]

Microsoft Excel can solve this problem if you know how to write it as a 13x13 matrix. You use MINVERSE and MMULT. But if you don't know linear algebra, well, you're gonna have a lot of trouble. At least all the variables turn out to be positive integers!

PS -- I ain't nevah got dat avi, an' don' plan t'get it neithah.

[AySz88]

Not since my undergrad days have I tried to invert a 13x13 matrix without a computer math software, but somehow I succeeded using Excel. Also I realised that I can write a matrix inversion program using Excel, have not seen that before, so that was definitely worth spending an hour and half of my life..

Just to let you all know that not everyone has the same set of numbers - but the answers will be the same.

This cannot happen - the set of numbers are unique. If I be a little bit techie here, this is because the underlying matrix is non-singular (in maths term). Or in other words you cannot have one of the equation derived from a combination of any other equations, so 13 equations and 13 variables will lead you to unique set of answers.

I agree with neomanias answer, but as Murphys law says that if LC is out always during daytime (in HI) whenever they have maths questions, or something similar, (except when LC is a hybrid of Maths and non-Maths like that sudoku and Xweetok thing couple of weeks ago) I am going to miss the avi again.

If you just add one to c and subtract one from d, for example, you end up with the same final answer, even though each individual letter is different.

[sid_basu4243]

If you just add one to c and subtract one from d, for example, you end up with the same final answer, even though each individual letter is different.

No, it does not satisfy 5d + 2c = 6m. Please check.

[ellobe]

I don't have math software If I had I could do it