# HSC 2016 General Maths Marathon (1 Viewer)

Status
Not open for further replies.

#### davidgoes4wce

##### Well-Known Member
This question was from the 2016 Sydney Grammar Trials

any idea on why they have used a radius of 6365 km and 6374 km to figure out the smallest surface area and largest surface area?

#### pikachu975

##### I love trials
Moderator
This question was from the 2016 Sydney Grammar Trials

any idea on why they have used a radius of 6365 km and 6374 km to figure out the smallest surface area and largest surface area?
It says to the NEAREST 10 KM. This means it could've been rounded from 6365 UP or 6374 DOWN. Those two are the respective smallest and largest it could've been.

#### davidgoes4wce

##### Well-Known Member
My initial estimates were 10 km up and 10 km down. 6380km and 6360 km .

Based on the solutions I now understand, 6365 km would be rounded up to 6370 km and 6374 km would be rounded down to 6370 km.

So now I'm guessing this topic would be under 'Rounding' numbers.

#### davidgoes4wce

##### Well-Known Member
Again this is from the 2016 Sydney Grammar Trials, just want to confirm this answer is correct or wrong? (This was written in the Sydney Grammar solutions)

Moderator

#### davidgoes4wce

##### Well-Known Member
I had a brain freeze, my student got this one right and I got it wrong yesterday. Surprisingly it took me another 12 hours to confirm it was right.

#### davidgoes4wce

##### Well-Known Member
This was a question from the 2016 Hurlstone Agricultural High School trials

One of my students who answered this question wrote down this:

Now I know the answer is \$17,473.68 but being a question that is only worth 1 mark, would my student still be able to get that mark despite putting an answer of \$3,473.68 down?

If you were a HSC marker would you give it? or not?

#### BLIT2014

##### The pessimistic optimist.
Moderator
This was a question from the 2016 Hurlstone Agricultural High School trials

One of my students who answered this question wrote down this:

Now I know the answer is \$17,473.68 but being a question that is only worth 1 mark, would my student still be able to get that mark despite putting an answer of \$3,473.68 down?

If you were a HSC marker would you give it? or not?
Unlikely to get given it.

#### davidgoes4wce

##### Well-Known Member
From the 2016 Sydney Grammar Trials:

Q22 MCQ

A machine produces 6000 items in a week. To obtain a systematic sample of 200, we could start with the 10th item and then select item numbers:

(A) 40,70,100,130,........
(B) 200,400,600, 800.........
(C) 100, 190, 280, 370,...........
(D) 210,410,610,810,.......................

Knowing that arithmetic series is not taught in General Maths....................I spent about 10 minutes thinking about it and still couldn't get the right answer.

#### davidgoes4wce

##### Well-Known Member
OK this was my thoughts.

If the first term in this sequence is 10. Knowing also that the difference is 30. We also know that there are 200 terms.

Another way Id do is to subtract the 6000 from 10 and divide by the difference of 30, which in this case gives close to the 200 mark sample.

#### davidgoes4wce

##### Well-Known Member
In Part B, If you subtracted (6000-10)/200= 29.5 (around 30 terms)

In Part C, If you subtracted (6000-10)/90=65.555 terms

In part D, if you subtracted (6000-10)/200=29.5 (like B you would get around 30 terms)

#### whatarethoose

##### Member
the way i did that question is if you need 200 samples from 6000 you just divide it

so it would be 30 for every sample

thus its a because 40, 70, 100

it goes up by 30

#### davidgoes4wce

##### Well-Known Member
Do Knox Grammar,
MLC and Caringbah have some sort of deal between the schools? The questions from the 2016 trials seem to overlap.

#### BLIT2014

##### The pessimistic optimist.
Moderator
Do Knox Grammar,
MLC and Caringbah have some sort of deal between the schools? The questions from the 2016 trials seem to overlap.
Might be some questions from a bought paper?

Status
Not open for further replies.