VCE General & Further Maths Question Thread!

[Lear]

Is it worth doing the NSW (HSC) bostes exam?

There are enough further exams available. I would not bother.

[Aaron]

Stick to VIC exams - if you do HSC ones, you have to sift through them and make sure the questions relate to the study design.. something you don't really have time to do, at this time of year.

[S_R_K]

You're right. But a counter argument is that it is 'more correct' as TVM incurs rounding errors whereas the table doesn't. I get 1187.9986 using table.

I got the same value (1187.99865079, on float12) using TVM solver.

First, I found the monthly payment to be 208.5024... This value is stored as –tvm.pmt.
Second, I found the balance of the loan after 24 payments to be 11183.9405... (I used the exact value of the monthly payment for this). This value is stored as -tvm.fv
Then I calculated the interest paid in the first two years by calculating 24*-tvm.pmt – (15000 – -tvm.fv). (ie. total paid in two years minus the principal reduction).

I believe there will be no rounding errors using this method.

[Lear]

I got the same value (1187.99865079, on float12) using TVM solver.

First, I found the monthly payment to be 208.5024... This value is stored as –tvm.pmt.
Second, I found the balance of the loan after 24 payments to be 11183.9405... (I used the exact value of the monthly payment for this). This value is stored as -tvm.fv
Then I calculated the interest paid in the first two years by calculating 24*-tvm.pmt – (15000 – -tvm.fv). (ie. total paid in two years minus the principal reduction).

I believe there will be no rounding errors using this method.

Yep I have attached an image of my method where I summed the Interest earnt column over the 24 months.


The answers claim it to be $1187.94 which then should be incorrect by roughly $0.06 when rounding to 2 d.p....right?

[S_R_K]

<snip>

The answers claim it to be $1187.94 which then should be incorrect by roughly $0.06 when rounding to 2 d.p....right?

Where is the question / answer from? Past VCAA exam?

I think your method gives a correct answer when rounded to 2 d.p.

[Lear]

Insight 2018 Exam I believe

I think the problem here is finding the monthly payment was a different sub question to the 2 year interest sub question. Insight used the rounded monthly payment from a) in order to find the interest incurred in part b)
Should we be using rounded for the next subquestion or exact?

[S_R_K]

Insight 2018 Exam I believe

<snip>

Is there any "hence" instruction, or any indication that the rounded answer from part a. is to be considered the actual monthly payment? (This is touching on issues in the other thread).

Otherwise, I'm inclined to think that Insight's answer is wrong, until I see evidence from VCAA that this kind of rounding is acceptable.

[Lear]

Is there any "hence" instruction, or any indication that the rounded answer from part a. is to be considered the actual monthly payment? (This is touching on issues in the other thread).

Otherwise, I'm inclined to think that Insight's answer is wrong, until I see evidence from VCAA that this kind of rounding is acceptable.

Appears they have used rounded in c) as it is a following sub question to b)

[PopcornTime]

Any advice for this question.

[PopcornTime]

Any advice for this question?

Got A, but answer is D.

[Lear]

Any advice for this question.

Here’s a hint :
Amount of principal paid off is Payment - Interest charged for each month.
As it’s reducing balance you’d expect the interest to decrease over time while the payments remains the same.

[Lear]

Any advice for this question?

Got A, but answer is D.

In my opinion answer should be C.
4200-600=3600

Interest for the year = 0.06*3600=216
Total to paid that year = 3600+216= 3816
3816/12=318

NOTE: Hire Purchase is No longer on the study design for 3/4 I think

[PopcornTime]

In my opinion answer should be C.
4200-600=3600

Interest for the year = 0.06*3600=216
Total to paid that year = 3600+216= 3816
3816/12=318

Yes it was C actually.

Also are these explanations ok.

Why interest decreases over time?
- for a reducing balance loan, payments are used to pay of the principal
- interest is calculated based on the outstanding principal value
- thus, as outstanding principal decreases, interest decreases

[galaxy21]

NOTE: Hire Purchase is No longer on the study design for 3/4 I think

Is hire purchase not just another term for simple interest? we got told that at school, so it will still be in the study design.

[Lear]

Is hire purchase not just another term for simple interest? we got told that at school, so it will still be in the study design.

Technically yes but there’s this weird question about effective interest rate on hire purchases that I’ve seen pop up often. Given that those don’t appear anymore I would expect hire purchases to also not be assessed.

Also hire purchase is specifically mentioned for units 1/2 but not 3/4