2008 Maths Competition (1 Viewer)

[imoO]

Re: Maths Competition

LOL...I guessed the number ones....I ran out of time and just wrote random ones.

1/1000 chance of getting it right.

0 should not be an answer so 1/999. It's looking better already

 

[ahhliss]

Re: Maths Competition

LOL...I guessed the number ones....I ran out of time and just wrote random ones.

1/1000 chance of getting it right.

0 should not be an answer so 1/999. It's looking better already

Lol I didn't even bother this time. I think I did for year 9 or something. My numbers were like 500 off lol.

 

[foram]

Re: Maths Competition

That's the one where numbers have a difference of 1 and are added together to make 2008 or something right? How do you do it? Sequences and series related?

The numbers have to add up to 2008.

So the AP which adds up to 1004 with a=1 and d=1

Sum of n terms = n(2a+(n-1)d)/2
=n(1+n)
=n^2 + n = 1004

using quadratic formular, n = 44.5...

doubling the number of terms, 2n = 89

 

[tommykins]

Re: Maths Competition

haha thats was a hard test, after about question 8 they really stepped up a level. what did every put for:

- 1000^2008, how many numerals?
- farmer with tanks
- the length of the rectange against the width Q ( the cross section of the cube was cut up)
-and Q27, about how many intersections occur as u draw lines from the lines midpoints to another midpoint within a cube.

any other questions too

1000 = 10^3 = (10^3)^2008 = 6024+1 times

 

[bored of sc]

Re: Maths Competition

1000 = 10^3 = (10^3)^2008 = 6024+1 times

Sweet: I got that. How many points was that worth? 4?

 

[summermagic]

Re: Maths Competition

The water tank I was just like add 10kL into the big tank since the small one was over 50% full and the big tank has more capacity LOL No calculations whatsoever xD


This is Westpac.

Is it? Cause when my friends did the working out, they reached a maximum, meaning that no matter what you do, the number of kL would be the same and hence they said the answer was e) Do nothing.

I however put one of the add 10kL ones so probably got it wrong lol.

 

[bored of sc]

Re: Maths Competition

Here are the question I remember (my answer in bold):

Which is larger:

(a) 2⁵⁰⁰ (b) 3⁴⁰⁰ (c) 4³⁰⁰ (d) 5²⁰⁰ (e) 6¹⁰⁰

If cos x = 0.5, which is larger?

(e) tanx (2 of the other answers were sinx, cos²x)

ratio of length to width for unit squares joined to make a cross shape then cut up to form a rectangle?

root6 : 2

Ratio of area of semi circle to triangle:

Um, something: pi : 2root3 I think.

 

[sirfeathers]

Re: Maths Competition

Is it? Cause when my friends did the working out, they reached a maximum, meaning that no matter what you do, the number of kL would be the same and hence they said the answer was e) Do nothing.

I however put one of the add 10kL ones so probably got it wrong lol.

No, you and ahhliss are right. The one where you added 10L from the small tank to the big tank was right because:

The small tank collected from a 80 sqm roof and the big tank roof collected from a 200 sqm roof. Ie. the volume of water collected by the big tank in a given time: vol of water collected by the small tank in a given time= 200:80 = 5:2.

If one tank fills up before the other, then additional rain will be "wasted" because because it will spill out of the full tank while the other tank is still being filled. Therefore, the most efficient collection of water would occur if the tanks fill up in such a way that they both reach full capacity at the same time. This will happen when the ratios of the volumes left in the tanks is proportional to the speed at which they fill up ie 5:2.

So ideally the big tank will have 5L of remaining capacity for every 2L the small tank has.

The small tank had 13/25L filled (ie room for +12L)
The big tank had 35/100L filled (ie room for +65L)

Therefore total free capacity is 12+65=77L
77L split into 5:2 parts is 55:22.

So to be most efficien:t the big tank should have 55L remaining capacity = 45L filled = 10L more than it normally contains
the small tank should have 22L remaining capacity = 3L filled = 10L less than it normally contains
So to reach these optimum capacities, 10L must be transferred from the small tank to the big tank.

 

[lolokay]

Re: Maths Competition

Here are the question I remember (my answer in bold):

Which is larger:

(a) 2⁵⁰⁰ (b) 3⁴⁰⁰ (c) 4³⁰⁰ (d) 5²⁰⁰ (e) 6¹⁰⁰

(4^3)^100 = 64^100
but (3^4)^100 = 81^100

 

[ahhliss]

Re: Maths Competition

The numbers have to add up to 2008.

So the AP which adds up to 1004 with a=1 and d=1

Sum of n terms = n(2a+(n-1)d)/2
=n(1+n)
=n^2 + n = 1004

using quadratic formular, n = 44.5...

doubling the number of terms, 2n = 89

Oooh I tried to make it equal to 2008 lol. I ended up with a huge number under a square root D:

(4^3)^100 = 64^100
but (3^4)^100 = 81^100

Ahs! I completely ignored the 100's when I was doing it (which doesn't sound very mathematical ) So I worked out 2^5, 3^4, 4^3, 5^2 and 6^1 I picked (b)

ratio of length to width for unit squares joined to make a cross shape then cut up to form a rectangle?

root6 : 2

Waaaaa I don't know why I made the assumption that the point was the midpoint and got 1:2 D: If I was doing that practise paper at home, I wouldn't let it go that easily because it doesn't look that bad. I spent hours per paper when I was doing them though o.0



Wow, that is a long explanation of the farmer's water tank xD I was just like the little tank is going to fill up quickly and cause overflow. I tried to calculate height or something but because of the time constraint I had, I just gave up and put (d) xD

The submerging the rectangular prism also got me confused D: I think I picked (b) 20something? I don't know how my working was but it matched whatever I had at the time lol. But then, they also put answers where students are likely to make mistakes and choose D:

 

[shaon0]

Re: Maths Competition

Are there ever any perfect scoreres in the Westpac?

 

[raiyan]

Re: Maths Competition

some ppl get perfect, its quite rare though..

 

[Rhanoct]

Re: Maths Competition

i had it p1&2 just after my ext eng morning exam, got through the first 20, saw the last ones and loled.

waste of timeee

 

[the-derivative]

Re: Maths Competition

Was it that hard? Was this Westpac or UNSW?

Westpac. The most crazy maths test in the world.

 

[lyounamu]

Re: Maths Competition

Westpac. The most crazy maths test in the world.

Hahahahaha... you wish.

Some random maths competition I did in Korea back in Yr 5 is as hard as the Wespac one I did in Yr 8 or 9.

 

[9megqyzn]

Re: Maths Competition

Fuck, what mark did you need for a distintion last year?

 

[lyounamu]

Re: Maths Competition

Fuck, what mark did you need for a distintion last year?

It's not mark. It's the percentile. You need to be top 15% to get distinction (i.e. for juniors). For seniors, it's like top 20-25%.

 

[Aerath]

Re: Maths Competition

Hmmm, No chance then. =\

 

[9megqyzn]

Re: Maths Competition

It's not mark. It's the percentile. You need to be top 15% to get distinction (i.e. for juniors). For seniors, it's like top 20-25%.

what was the mark for people who got top 15%?

 

[Aerath]

Re: Maths Competition

It's crazy being up this early - been paranoid about that test all night.

what was the cut off for last year's year 10 distinction heard it was 50/140

i got 57/140 and still mananged myself way into a distinction in year 9

You really should not stress out about it. It's nothing -that- big. By all means, do well, but don't lose sleep over it.