# Thread: Australian Maths Competition

1. ## Re: Australian Mathematics Competition

I reckon more like 70-80 for yr 12 and 60-70 for yr 11. I reckon the Senior Division was harder than past Senior Divisions

2. ## Re: How did u go in the Australian Maths Competition?

Originally Posted by maths94
today (6-8-09) i did my intermediate AMC test.This is just a thread to see which question u were stuck on ...q26-30:@ i need help on dem,, and ye just a general chat on how u went in the AMC test.
Here is my solution to 26 for ya =)

$Question 26: What is the smallest positive integer which, when divided by each of 2,3,4,5,6 and 7, will give in each case a remainder that is one less than its divisor?$

$Let the smallest number be x, then$

$x \equiv 1 \mod 2$

$x \equiv 2 \mod 3$
.
.
.
$x \equiv 6 \mod 7$

$Note that each of these equations can be expressed as follows,$

$x \equiv -1 \mod 2$

$x \equiv -1 \mod 3$
.
.
.
$x \equiv -1 \mod 7$

$Hence\,\, x + 1\,\, is a multiple of \,\,2,3,4,5,6,7$

$\therefore x + 1\,\, is a multiple of\,\,LCM[2,3,4,5,6,7] = 420$

$As 420 is the smallest multiple of 420$

$\implies x + 1 = 420$

$\therefore x = \boxed{419}$

3. ## Re: How did people go in the maths comp today?

Originally Posted by kurt.physics
No ;P

Could you post them possibly? (some of them could be the same so perhaps you could just kinda explain which ones or something)
Umm, I remember 27 so I'll try explaining that one.

27. A number is called Ascending if the digits are increasing. Eg. 123 and 2356 is ascending but 749 or 7799 is not. Find a 3 digit number that is Ascending and also has the property that 6n where n is the number is Ascending.

4. ## Re: How did u go in the Australian Maths Competition?

this is bs lol, i worked it out just like kurt.physics but instead of taking 1 off of x at the end i added it. and for question 29, im fairly sure that i got it right, but even if i did, it won't matter because i put that answer in the box for question 30.

oh noes, all the answers that i thought were right suddenly seem like they were wrong.

5. ## 2009 AMT Mathematics Competition

How was it? I personally found it harder than earlier years.
Feel free to discuss the test or any of the questions.
Did anyone confidently solve the last 5 questions?

6. ## Re: 2009 AMT Mathematics Competition

Originally Posted by spammy679
How was it? I personally found it harder than earlier years.
Feel free to discuss the test or any of the questions.
Did anyone confidently solve the last 5 questions?
The Westpac comp yeh?

Yeh, I did the Senior Divison and I found that it was really difficult compared to past senior papers.

I'm confident I got 26 and 27 correct.

7. ## Re: 2009 AMT Mathematics Competition

Originally Posted by Official
The Westpac comp yeh?

Yeh, I did the Senior Divison and I found that it was really difficult compared to past senior papers.

I'm confident I got 26 and 27 correct.
How did you solve 27?

8. ## Re: 2009 AMT Mathematics Competition

Originally Posted by kurt.physics
How did you solve 27?
Well I knew the last digit of the answer had to be a relatively large number because it is an Ascending number. So I assumed that the last digit of n had to be 8. (6*8) = 48, has 8 as a last digit.

From that step, I pretty much used trial and error of 3 digit numbers, keeping 8 as the last digit. Eventually, I came to the solution: 578. 578 * 6 = 3468, which is also an Ascending number.

9. ## Re: How did people go in the maths comp today?

it was easier than last year's. I'm scared the machine won't be able to read my answers, because I didn't colour dark enough.

10. ## Re: How did people go in the maths comp today?

Official did you have the rabit question in your exam, i got the minimum number of rabits is 31. Did you get this?

11. ## Re: 2009 AMT Mathematics Competition

nice, Official. I almost got that except I gave up when I got to 570.

12. ## Re: 2009 AMT Mathematics Competition

Originally Posted by nerdsforever
nice, Official. I almost got that except I gave up when I got to 570.
Yeh, nice. For that question i cbf even trying, I despise brute force!!!

13. ## Re: How did people go in the maths comp today?

Originally Posted by kurt.physics
Official did you have the rabit question in your exam, i got the minimum number of rabits is 15. Did you get this?
Oh, nope sorry, I didn't have that question.

14. ## Re: 2009 AMT Mathematics Competition

I only got one out of the last 5...question 27 was 578. I firstly ruled out the numbers that couldn't be at the end or middle and then it boiled down to a possibilty of like 10 which I tested and only one worked.

15. ## Re: How did u go in the Australian Maths Competition?

I didn't get any of the last ones but the multiple choice where easier than I expected. Still, I expect i failed.

16. ## Re: How did people go in the maths comp today?

Originally Posted by Official
Oh, nope sorry, I didn't have that question.
What was the 26 senior question?

17. ## Re: 2009 AMT Mathematics Competition

Originally Posted by gurmies
I only got one out of the last 5...question 27 was 578. I firstly ruled out the numbers that couldn't be at the end or middle and then it boiled down to a possibilty of like 10 which I tested and only one worked.
Nice . How do you think you went in general, and what do you think the HD cut off will be this year?

18. ## Re: How did people go in the maths comp today?

Originally Posted by kurt.physics
What was the 26 senior question?
It was something along the lines of:

The reciprocal of 4 numbers add up to make a total of 19/20. 3 numbers are in the ratio of 1:2:3. Find the sum of the 4 numbers.

There could have been more detail but if there was, I can't remember

19. ## Re: How did people go in the maths comp today?

integers for question 26...i've got the paper here so I can post any requested questions.

20. ## Re: How did people go in the maths comp today?

lol the map question
my friend actually folded paper for that one

21. ## Re: How did people go in the maths comp today?

Originally Posted by Hypermelon
lol the map question
my friend actually folded paper for that one
Same here hehe.

22. ## Re: How did people go in the maths comp today?

Can you remember what answers you came to, i got (E)?

23. ## Re: How did people go in the maths comp today?

LOL same here. That's one of the ones I got wrong -_-

24. ## Re: How did people go in the maths comp today?

Originally Posted by kurt.physics
Can you remember what answers you came to, i got (E)?
For the map question I got the option where the 3rd letter is W. Besides that I can't remember

25. ## Re: How did people go in the maths comp today?

yeah, i folded the map question and i got E.

Page 4 of 26 First ... 2345614 ... Last

##### Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•