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UNSW maths comp (1 Viewer)

inasero

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Did anyone do it....how #@%#!$ impossible was it!! I hope you all agree with me here...cos if u guys didn't I would feel extremely dumb....HEck!! I feel dumb anyway!!
 

turtle_2468

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Can someone post a copy? Text or whatever form is fine... just for nostalgic value :p

BTW, usually UNSW comps are meant to be quite hard. For example, solve 3 questions out of 6 and u get some money... or something like that
 

Constip8edSkunk

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only got 2 and a bit out :( some guy from our school got 5 out of teh 6:eek:

newayz We werent allowed to take the paper out....

but theres this question that i had absolutely no idea: 8889 cards with 5 digit numbers 11111 upto 99999 are randomly arranged 2 form a 44445 digit number. Show that there are no possible combinations where the resulting number is a power of 2003.

:confused: :confused: :confused:
 
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spice girl

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Originally posted by Constip8edSkunk
but theres this question that i had absolutely no idea: 8889 cards with 5 digit numbers 11111 upto 99999 are randomly arranged 2 form a 44445 digit number. Show that there are no possible combinations where the resulting number is a power of 2003.
ooh...i know how to do this one:

if N is a 44445-digit number, then 10^44444 < N < 10^44445

N = 2003^x
10^44444 < 2003^x

log both sides
44444ln10 < xln2003

similarly, xln2003 < 44445ln10

you'll find that x can never be an integer (since you're allowed to use a calculator)
 
N

ND

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Originally posted by inasero
Did anyone do it....how #@%#!$ impossible was it!! I hope you all agree with me here...cos if u guys didn't I would feel extremely dumb....HEck!! I feel dumb anyway!!
Damn, why do i never hear about these things....
 

Harimau

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Originally posted by inasero
Did anyone do it....how #@%#!$ impossible was it!! I hope you all agree with me here...cos if u guys didn't I would feel extremely dumb....HEck!! I feel dumb anyway!!
Thanks for telling me about it Wilson... and man do i feel dumb looking at that one question. :(
 

inasero

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oops sorry i forgot to remind you there textbook :p but anyways i don't think you woudl have had much success anyways...as I said it's bloody impossible~~
 

SoFTuaRiaL

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thats UNSW for u !!
try doing discrete maths as one of ur subjects if u decide to go to unsw ...
 

Newbie

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heard one of our guys got 5/6 right lol
wot a nut
 

xiao1985

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Originally posted by spice girl
ooh...i know how to do this one:

if N is a 44445-digit number, then 10^44444 < N < 10^44445

N = 2003^x
10^44444 < 2003^x

log both sides
44444ln10 < xln2003

similarly, xln2003 < 44445ln10

you'll find that x can never be an integer (since you're allowed to use a calculator)

lolz, wut can i say... dat's very smart...... >< y didn't i think of that in that comp!!! :'( any hoo i did the comp and ..... oh boy, tis hard alrite..... i spend like 4 hrs on 1 q, and still couldn't get it out......

btw, any one got 5/6 q's that person's either a math freak or a math freak...... no offence tho, i adore math freaks..... i want to be one but i can't... too hard...
 

maniacguy

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Really? I thought some of the questions were too easy for the test (relatively speaking). For example there was an inequalities question that came out pretty easily.

[I'm basing my judgement on the fact that you were allowed to take in any number of books, calculators, etc.]

Overall some of the questions in the Junior section were harder than those in the Senior, but the general standard was about right I guess, since the hard questions did offset the easy ones.

That question was one of the hard ones, yes.

Incidentally, spice girl, your solution isn't actually the one the person who wrote the question came up with. His solution was a modular arithmetic method (I forget the modulus though).

So you'll probably have your solution coming out as an alternative when the official solutions are released :)

There was a question making a play on the Iraq situation but it didn't get through (George and Maddas are playing a game. Who wins? If it had been 2002 who would have won? - The question involved the number 2003, and it turned out George wins this year, but Maddas would have won last year)
 

dopez

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I used modular arithmetic. Use mod 9 - there are a bunch of rules which apply when using it. It's not hard if u do that.
 

Constip8edSkunk

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Im guessing you go2 his tutoring rite?



Originally posted by xiao1985

btw, any one got 5/6 q's that person's either a math freak or a math freak...... no offence tho, i adore math freaks..... i want to be one but i can't... too hard...
well he got in2 IMO, so yeah....
 

xiao1985

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Originally posted by Constip8edSkunk

well he got in2 IMO, so yeah....
woa?? gee, wut's his name?? i prolly noe him, knowin he's dat famous dat is.........
 

Newbie

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ivan guo
and his only in year 9 or something
 

Constip8edSkunk

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dopez: no i was refering to maniacguy cuz the guy who set the comp is a tutor in the city.

ivan guo is in yr 11
 

xiao1985

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woa..... all smart pplz..... :'( no hope 4 me to get 90+ uai now.......
 

Wacky

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triangle inequality question

Does anyone iknow how to do the second part of the inequality question? The first part was straight from the book that I got but I couldn't get it out.

Ended up doing around 2.5 questions...

I think the first one was real easy.
 

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