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HSC 2012 MX1 Marathon #2 (archive) (2 Viewers)

bleakarcher

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Re: HSC 2012 Marathon :)

Well yes its not. Coming up with it out of no where though is.
 

bleakarcher

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Re: HSC 2012 Marathon :)

gunna have a shower. better come back to a good maths problem (orite realise).
 

barbernator

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Re: HSC 2012 Marathon :)

heres a good one, from CSSA q6 a) i) 2004.

"prove the riemann hypothesis"
 

deswa1

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Re: HSC 2012 Marathon :)

heres a good one, from CSSA q6 a) i) 2004.

"prove the riemann hypothesis"
No worries, I'll get on it right away :) BTW, I think it was more Q2 (they never put complex questions this easy that late I don't think)
 

bleakarcher

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Re: HSC 2012 Marathon :)

I thought you guys were serious, full searching for the CSSA 2004 paper LOL..
 

bleakarcher

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Re: HSC 2012 Marathon :)

^ lol. also, where the fuck is realisenothing?
 

RealiseNothing

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Re: HSC 2012 Marathon :)

We have a circular table of 9 seats, which are being used to seat guests for a dinner.

The guests are the numbers 1 through to 9.

How many different seating arrangements are there for the 9 numbers given that if we take any two numbers sitting next to eachother, their sum is less than or equal to 11.

Take clockwise and anti-clockwise to be a different arrangement.
 

bleakarcher

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Re: HSC 2012 Marathon :)

goddamnit, i dont know much probability, its the last topic i need to work on.
 

barbernator

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Re: HSC 2012 Marathon :)

16 i think if my idea of anticlockwise/clockwise is correct.
 
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RealiseNothing

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Re: HSC 2012 Marathon :)

ive got a good one, it is quite hard and i want to see full solutions. :D

part a) A single wheel line of a railway line is being laid when the temperature is a constant 0 degrees. The expansion of the track as heat increases is 0.01cm^3/degree/1cm^3 of metal laid. If the track must be 5cm high, and 8cm wide for the train to run on it properly, and expansion occurs as the temperature increases width ways, height ways, and length ways equally relative to the measurement (i.e. if a block is 1x2x3, the ratio of expansion over distance would be equal per dimension).

The track must be laid over a distance of 100m.

How much metal(volume) must be used initially at temp 0 degrees and what dimensions must it be laid in as a single piece.

If the temperature when the line is being used is a constant 20 degrees.

part b) For some crazy reason, i think they call it "weather", the temperature varies between 18 and 22 degrees while the train is in operation. This means the track shrinks and expands. How much volume of metal(sliced acrossways) must be cut out from the track to ensure it never expands to a longer length than 100m. If the length of the gap from where the metal was cut out cannot exceed 2cm at any temp within operation range, assuming all cuts were made at 20 degrees temp, what is the minimum number of cuts that can be made to satisfy the first condition in part b and the 2cm rule. (for this part, when the track expands, the height and width of the track will change, but this doesnt matter).

Have fun lol. if there is any indiscrepancy, tell me.

infinite respect if someone gives a good solution to this.
Whatever, not like I needed to sleep tonight.
 

RealiseNothing

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Re: HSC 2012 Marathon :)

ive got a good one, it is quite hard and i want to see full solutions. :D

part a) A single wheel line of a railway line is being laid when the temperature is a constant 0 degrees. The expansion of the track as heat increases is 0.01cm^3/degree/1cm^3 of metal laid. If the track must be 5cm high, and 8cm wide for the train to run on it properly, and expansion occurs as the temperature increases width ways, height ways, and length ways equally relative to the measurement (i.e. if a block is 1x2x3, the ratio of expansion over distance would be equal per dimension).

The track must be laid over a distance of 100m.

How much metal(volume) must be used initially at temp 0 degrees and what dimensions must it be laid in as a single piece.

If the temperature when the line is being used is a constant 20 degrees.

part b) For some crazy reason, i think they call it "weather", the temperature varies between 18 and 22 degrees while the train is in operation. This means the track shrinks and expands. How much volume of metal(sliced acrossways) must be cut out from the track to ensure it never expands to a longer length than 100m. If the length of the gap from where the metal was cut out cannot exceed 2cm at any temp within operation range, assuming all cuts were made at 20 degrees temp, what is the minimum number and length of EQUAL LENGTH cuts that can be made to satisfy the first condition in part b and the 2cm rule. (for this part, when the track expands, the height and width of the track will change, but this doesnt matter).

Have fun lol. if there is any indiscrepancy, tell me.

infinite respect if someone gives a good solution to this.
Can you explain what I bolded. Does that mean, since the temperature goes from 0 to 20, it becomes 0.2cm^3/20degrees/20cm^3 of metal laid?
 

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