2012 Year 9 &10 Mathematics Marathon

**Demento1** · 1 Oct 2012, 12:39 AM

Originally Posted by kazemagic

O_O so theres no other methods to do this unless trial and error?

I call it 'systematic listing' to suit a certain case. Don't make it sound silly. Example: Draw up a table of values if that works.

**kazemagic** · 1 Oct 2012, 12:39 AM

Originally Posted by enoilgam

So far, the petal question and the last two I posted all came from the same year 9 5.3 test. However, that year 9 test is easily the hardest I have ever seen and the time limit was ridiculous (45 minutes).

yea... i wonder which school...

**Sy123** · 1 Oct 2012, 12:40 AM

Originally Posted by kazemagic

O_O so theres no other methods to do this unless trial and error?

I wouldnt call it trial and error simply because it only takes 1 'trial' if you know what you are doing in terms of triads

Originally Posted by HSC2014

I overlooked this bit

So that's why going into equations and stuff didn't work so well. Integers integers integer.

Does a math question ever include redundant information which is not necessary to like... trick someone? Like for the triangle question they could have included 12m^2 as the area but make it so that it is not necessarily required to achieve the answer, and thus your thinking would be stuffed up due to incorporating that piece of info.

In the HSC this rarely happens I would think, every hard question they give they lead you towards the answer through various parts.

Like for example in one hard end question they ask you 4 parts
you get part 1 and 2, and then use these parts to get 3, and then 4 or something like that. So in the HSC they moreso lead you onto the answer (still need to do some good thinking for the harder questions)

**enoilgam** · 1 Oct 2012, 12:42 AM

Originally Posted by kazemagic

yea... i wonder which school...

Its not a high ranking selective/private school or anything. Personally, although I think this paper had some great questions, the school's maths department is pretty poor.

**Fawun** · 1 Oct 2012, 12:44 AM

Originally Posted by SpiralFlex

Lol I didn't see it, what was your working?

Originally Posted by Fawun

$\frac{1}{2}\pi r^2 = \pi r + 2r$

$\pi r^2 = 2\pi r + 4r$

$\pi r^2 = 2r (\pi + 2)$

$\frac{\pi r^2}{2r} = \pi + 2$

$\frac{\pi r}{2} = \pi + 2$

$\pi r = 2 \pi + 4$

$r = \frac{2 \pi + 4}{\pi}$

THANK YOU TO THE EPIPHANY THAT I JUST HAD

Originally Posted by Shazer2

I seriously haven't known how to do 1 question in this thread

i know that feel

**kazemagic** · 1 Oct 2012, 12:46 AM

Originally Posted by Sy123

I wouldnt call it trial and error simply because it only takes 1 'trial' if you know what you are doing in terms of triads

In the HSC this rarely happens I would think, every hard question they give they lead you towards the answer through various parts.

Like for example in one hard end question they ask you 4 parts
you get part 1 and 2, and then use these parts to get 3, and then 4 or something like that. So in the HSC they moreso lead you onto the answer (still need to do some good thinking for the harder questions)

lol i wud have never thought of using the triads

Originally Posted by enoilgam

Its not a high ranking selective/private school or anything. Personally, although I think this paper had some great questions, the schools maths department is pretty poor.

i wonder if anyone got 100 in that

**enoilgam** · 1 Oct 2012, 12:47 AM

Originally Posted by kazemagic

i wonder if anyone got 100 in that

The average was abysmal (like 15%) - to be honest, the test wasnt very well thought out. I mean, I dont mind a hard paper but this was beyond reasonable.

**kazemagic** · 1 Oct 2012, 12:48 AM

Originally Posted by enoilgam

The average was abysmal (like 25%) - to be honest, the test wasnt very well thought out. I mean, I dont mind a hard paper but this was beyond reasonable.

yep even my tutor tests arent even that hard

**Demento1** · 1 Oct 2012, 12:49 AM

Originally Posted by enoilgam

The average was abysmal (like 15%) - to be honest, the test wasnt very well thought out. I mean, I dont mind a hard paper but this was beyond reasonable.

I question Carrot's 3U and 4U papers.

**enoilgam** · 1 Oct 2012, 12:51 AM

Originally Posted by kazemagic

yep even my tutor tests arent even that hard

The average was actually 15% (typo).

Originally Posted by Demento1

I question Carrot's 3U and 4U papers.

The thing is, carrots papers were designed specifically to be an absolute worst case scenario. Also, the difficulty was kept within reason.

**SpiralFlex** · 1 Oct 2012, 12:52 AM

Carrot's papers are definitely within reason but require deeper thinking and to catch out them rote learners. It's guided as the HSC.

**Demento1** · 1 Oct 2012, 12:55 AM

Originally Posted by SpiralFlex

Carrot's papers are definitely within reason but require deeper thinking and to catch out them rote learners. It's guided as the HSC.

I respect the fact that he comes up with all sorts of interesting problems. It takes me days and holidays to think of like two questions - the penny dropped in one of them when I was on a ride in Seaworld.