# 2009 Mathematics 2U HSC Worked Solutions (1 Viewer)

#### T.Goodhew

##### Actuarial Co-op 06
Hi everyone,

Please find "sample solutions" to the 2009 Mathematics (2 Unit) HSC Exam at 2009mathsHSCsoln_v1.2.pdf. (Updated Solutions, all errors fixed)

I realise there is another thread offering solutions however that only shows the final answers.

Before viewing the solutions please understand:

• The solutions are not endorsed in any way by NSW Board of Studies
• These are only "sample solutions" there may be more than one way to correctly answer a question
If you do find any errors in the solutions, please post them here.

Cheers and Good Luck with the rest of your exams
Tim

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#### Scinery

##### Member
oh fml that was a depressing read

should not have read that

#### maryBRAHS

##### :)
oh fml that was a depressing read

should not have read that
LOL well it is 3.30 am so go to bed and relax! its over now.
start to get depressed when the results come out :|

#### boxhunter91

##### Member
He missed out that drawing question on q8..
Looks like i done preety well.

#### mtsmahia

##### Member
anyone have the Q paper?

#### Thecorey0

##### Member
Thanks dude. Q5cii2 seems to be wrong. The triangle is an equilaterial, and hence all sides are 2. In your working you have forgot the '2' in the -2absinc bit. The answer should be 2 + 2pi/3. It's good to know my answers are right. I can now say confidently that I got 114-115.

#### boxhunter91

##### Member
Gratz Thecorey.
Im sitting on at least 105.

#### Thecorey0

##### Member
Gratz Thecorey.
Im sitting on at least 105.
That's still a decent band 6. Hopefully someone smarter then us can confirm q8a.

#### tku336

##### Member
Fuck. I wrote the answers down on my sheet, so now I know exactly how many stupid mistakes I made. 110-112, with 6 marks worth of stupid errors.

P.S. Can somebody explain why 9a) everybody multiplied the chances? Surely multiplication means AND, nor OR. You should have added 8/9 + 15/16, cubed that, then 1- that., surely.

#### Thecorey0

##### Member
Fuck. I wrote the answers down on my sheet, so now I know exactly how many stupid mistakes I made. 110-112, with 6 marks worth of stupid errors.

P.S. Can somebody explain why 9a) everybody multiplied the chances? Surely multiplication means AND, nor OR. You should have added 8/9 + 15/16, cubed that, then 1- that., surely.
Well the odds that neither of them win in any given week = 8/9*15/16 =5/6. Hence the odds that they don't win for 3 continious weeks - i.e. don't win at all = (5/6)^3. Therfore the odds of winning at least once is 1 - (5/6)^3 = 91/216.

#### tku336

##### Member
Eh. I'll get 1/2 for that anyway. Do you know what a 110-112 would align to?

#### Melisoverschool

##### Member
hmmm..i think i did better than i thought....nowhere near you guys but around 80 i think

#### possessionless

##### Banned
im not going to read that. ill end up comitting suicide if i do LOL.

bye sydney uni, nice dreaming of you

#### absorber

##### Member
I think your answer with the savings question is wrong, I got something like \$129966 as opposed to your \$128k; and I'm not alone.

Is it because you rounded up the payments to 179? he didn't need a full payment the last time, like .4 of a payment or something, hence shouldn't be regarded as a full payment

#### T.Goodhew

##### Actuarial Co-op 06
Thanks dude. Q5cii2 seems to be wrong. The triangle is an equilaterial, and hence all sides are 2. In your working you have forgot the '2' in the -2absinc bit. The answer should be 2 + 2pi/3. It's good to know my answers are right. I can now say confidently that I got 114-115.
Absolutely correct, thanks for pointing that out!

*Solutions updated*

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#### T.Goodhew

##### Actuarial Co-op 06
I think your answer with the savings question is wrong, I got something like \$129966 as opposed to your \$128k; and I'm not alone.

Is it because you rounded up the payments to 179? he didn't need a full payment the last time, like .4 of a payment or something, hence shouldn't be regarded as a full payment
This is also correct, although the answer will vary between \$129965 and \$129966 depending on where you have rounded in your working. At first glance, I had thought a broad brush calculation would suffice but in hindsight you are absolutely correct and the fractional monthly repayment should have been dealt with correctly.

*Solutions updated*

B

#### babypunk313

##### Guest
hey, im only lookin at gettin about 90ish but in Q7,a,ii:
(u+1)(4u-1) would make 4u^2+3u-1, wouldnt it? you're meant to get 4u^2+3u+1.
i tried to do it in the test but i couldnt get past that

#### BobbyBobbyBob

##### New Member
Can anyone post up / link me to the exam paper?