2008 Maths Competition (3 Viewers)

[Doctor Jolly]

Re: Maths Competition

Far out. I died in that test. I stopped caring after Q20 and put in random numbers for 25-30 because I didn't know what to do. And did anyone find the question with 'cool' in it totally, uncool? It was a really weird question.

With the farmer question, i think I chose (b) because I didn't know what b was asking, so I just chose that one. All the rest of the questions led to 77kL if my serves me correct.

LOL. I also got stuck on the last question on the first page - stupid ratios.

I missed my calculator during that exam

 

[jellybelly59]

Re: Maths Competition

Far out. I died in that test. I stopped caring after Q20 and put in random numbers for 25-30 because I didn't know what to do. And did anyone find the question with 'cool' in it totally, uncool? It was a really weird question.

With the farmer question, i think I chose (b) because I didn't know what b was asking, so I just chose that one. All the rest of the questions led to 77kL if my serves me correct.

LOL. I also got stuck on the last question on the first page - stupid ratios.

I missed my calculator during that exam

ROFL me too >.<"

 

[Doctor Jolly]

Re: Maths Competition

Lol I'm used to pressing EVERYTHING into my calculator. It's only when I'm doing something with not much calculations and I'm too lazy to grab my calculator that I use my head. Doing practise papers and the Maths Comp I was dividing, multiplying, squaring, adding and subtracting on paper. It was weirddd.

yeah after the SC I clung onto my calculator more because I knew that I would never see another non-calculator exam again .. how wrong I was.

 

[bored of sc]

Re: Maths Competition

Lets just agree the test was terribly difficult. :uhhuh:

 

[foram]

Re: Maths Competition

Lets just agree the test was terribly difficult. :uhhuh:

I could have done the first 25 questions + the cool question. if i had a bit more time.

 

[The Kaiser]

Re: Maths Competition

If anyone still remembers or cares (probably not), the way to work the last question (30) is this.

1. Complete the squares of the first and last equations and from this find the minimum value from A and B respectively (7 and 5 respectively)

2. Substitute these values in the 2nd equation and find the value (12)

3. Add the three values together (Thus my answer was 24)

However, I think I made a careless mistake (no damn calculators) but I'm pretty sure that was the way to work it out.

 

[bored of sc]

Re: Maths Competition

I could have done the first 25 questions + the cool question. if i had a bit more time.

High distinction and/or prize for you then.

 

[lyounamu]

Re: Maths Competition

I should have done this...Ahhhhh!

 

[SL11]

Re: Maths Competition

Question 28 was the only one I worked out in the last 5, using good old guess and check.

 

[Doctor Jolly]

Re: Maths Competition

Ooh. I thought of completing the square but I was just like :S during the test. I substituted random numbers and hoped it would work D: I kept getting surds lol.

a was 7? I thought it had to be something root2 to get rid of the root2 it was multiplied with?

I honestly didn't know what I was doing for that question. But I ended up getting 35. Don't ask.

 

[The Kaiser]

Re: Maths Competition

Ooh. I thought of completing the square but I was just like :S during the test. I substituted random numbers and hoped it would work D: I kept getting surds lol.

a was 7? I thought it had to be something root2 to get rid of the root2 it was multiplied with?

Middle term was 14 root 2 (I think), completing the square would give you 98 as the constant term, I don't remember what the last term was, but for that equation I got 49 and since it was a root, I came up with 7.

 

[SL11]

Re: Maths Competition

What was 28?

I think it was 3x^2 - 8y^2 + 3x^2y^2 = 2008, find xy.

 

[The Kaiser]

Re: Maths Competition

I think it was 3x^2 - 8y^2 + 3x^2y^2 = 2008, find xy.

I guessed 72 (I know I'm wrong)

What was your answer?

 

[SL11]

Re: Maths Competition

I guessed 72 (I know I'm wrong)

What was your answer?

Ironically, 28 for question 28. I had x=4, y=7

 

[shaon0]

Re: Maths Competition

If anyone still remembers or cares (probably not), the way to work the last question (30) is this.

1. Complete the squares of the first and last equations and from this find the minimum value from A and B respectively (7 and 5 respectively)

2. Substitute these values in the 2nd equation and find the value (12)

3. Add the three values together (Thus my answer was 24)

However, I think I made a careless mistake (no damn calculators) but I'm pretty sure that was the way to work it out.

Yes! I was right! I was showing people how to do the last question on the Westpac.

 

[Iruka]

Re: Maths Competition

hmm...

Maple believes the minimum value of that expression is 13 which occurs at a=35sqrt(2)/17 and b=35/12.

 

[electrolysis]

Re: Maths Competition

lol i guessed 9 for the last one, and this other guy in my class also guessed 9... weird

 

[electrolysis]

Re: Maths Competition

Yes! I was right! I was showing people how to do the last question on the Westpac.

you didnt explain anything after saying to complete the square...

 

[lolokay]

Re: Maths Competition

I think it was 3x^2 - 8y^2 + 3x^2y^2 = 2008, find xy.

wow, how'd you manage to guess that?
you could write that as (3x^2 - 8)(y^2 + 1) = 2000
then go through the factors of 2000 til you come across ones that are one more than a perfect square, then test.

 

[Iruka]

Re: Maths Competition

wow, how'd you manage to guess that?
you could write that as (3x^2 - 8)(y^2 + 1) = 2000
then go through the factors of 2000 til you come across ones that are one more than a perfect square, then test.

That's exactly how you do it. It's a Diophantine equation. This particular one had only one solution.