All About Math Olympiad Training & Questions

[clover18]

MathsOlympiadtrainer:

clover18:

Contest format

There will be two categories in the contest, the Junior Category and the Open Category.
The Junior Category will be open to all Primary 1 – 5 pupils.
The Open Category will be open to all Primary 6 pupils.
There is no age limit for either category of pupils.

Round 1 is for all participants. It will be a 60 minutes online test, consisting of 20 multiple-choice questions. Participants will take the test from their respective primary schools.

Round 2 is only for the top 50 participants from each of the Junior and Open categories succeeding from Round 1. It will be a 60 minutes written paper, consisting of 15 open ended questions. Participants from Singapore schools will take this test in Raffles Institution.


Hello all. I was reading the above and noticed this year there is less than 50 toppers in both the junior and open category ( aout 38 in each). Does it mean one has to get to round 2 to score a distinction? Or since less than 50 went to round2, some of the kids may have been top 50 (with distinction) and not invited to round 2? TIA.

The toppers from both the categories in Round 1 will be invited for Round 2 of the contest.
Based on the final results of both rounds:
Ranks 1 to 15 will be awarded a Trophy and Certificate of High Distinction.
Ranks 16 to 50 will be awarded Certificate of Distinction.
Ranks 51 to 120 will be awarded a Certificate of Credit.
-Copied from RI website-




Last year, top 50 was chosen for round 2 whereas this year, top 30 instead of 50 is selected.

For more information,
http://contests.heymath.com/admin/RI13

So those not selected will still stand a chance for distinction.

Cheers.

Thanks for clarification; so it's still top 50 for distinction even though fewer were invited to round 2. Clear now... Thanks!

[empressplace]

I just chanced upon this thread and post. Sorry for my ignorance but could someone please explain to me why there is only one combination for 4 in one box? There are 4 boxes. So shouldn't there be 4 ways to put the 4 marbles in one box?

quekcc:

trileets:

May I know how this qn is done?

Find the number of ways to put 4 different coloured marbles into 4 identical empty boxes.

Ans: 15 (my ans of 24 is wrong)



TIA

Your answer 24 is the number of ways to arrange 4 different coloured marbles in order. But the question is looking for number of ways to group the 4 different coloured marbles.

There are 5 possible ways of grouping.

1) all in 1 box - 1 possible combination only
2) 3 in 1 box and 1 in another box - 4 possible combinations
3) 2 in 1 box and 2 in another box - 6 possible combinations
4) 2 in 1 box, 1 in 2nd box and 1 in another box - 3 possible combinations
5) 1 in each box - 1 possible combination only

So total = 1 + 4 + 6 + 3 + 1 = 15

[clover18]

Hi, can someone advise if competitions like Gauss contest and AMC carry much weight in DSA applications?

[dagong99]

clover18:

Hi, can someone advise if competitions like Gauss contest and AMC carry much weight in DSA applications?

Besides Maths Hub, do you know any other centre holding AMC ? Maths Hub used to hold it in Bt Timah Branch too but this year, they don't.

[clover18]

dagong99:

clover18:

Hi, can someone advise if competitions like Gauss contest and AMC carry much weight in DSA applications?

Besides Maths Hub, do you know any other centre holding AMC ? Maths Hub used to hold it in Bt Timah Branch too but this year, they don't.

I had the impression Mathshub hold it at all their branches. Perhaps you can also check Maths Oasis?

[MathsOlympiadtrainer]

empressplace:

I just chanced upon this thread and post. Sorry for my ignorance but could someone please explain to me why there is only one combination for 4 in one box? There are 4 boxes. So shouldn't there be 4 ways to put the 4 marbles in one box?

quekcc:

[quote=\"trileets\"]May I know how this qn is done?

Find the number of ways to put 4 different coloured marbles into 4 identical empty boxes.

Ans: 15 (my ans of 24 is wrong)



TIA

Your answer 24 is the number of ways to arrange 4 different coloured marbles in order. But the question is looking for number of ways to group the 4 different coloured marbles.

There are 5 possible ways of grouping.

1) all in 1 box - 1 possible combination only
2) 3 in 1 box and 1 in another box - 4 possible combinations
3) 2 in 1 box and 2 in another box - 6 possible combinations
4) 2 in 1 box, 1 in 2nd box and 1 in another box - 3 possible combinations
5) 1 in each box - 1 possible combination only

So total = 1 + 4 + 6 + 3 + 1 = 15

[/quote]the boxes are identical so the way to put 4 different marbles in 4 identical is only 1.

[dagong99]

clover18:

dagong99:

[quote=\"clover18\"]Hi, can someone advise if competitions like Gauss contest and AMC carry much weight in DSA applications?

Besides Maths Hub, do you know any other centre holding AMC ? Maths Hub used to hold it in Bt Timah Branch too but this year, they don't.

I had the impression Mathshub hold it at all their branches. Perhaps you can also check Maths Oasis?[/quote]I went to Maths Hub last week, they mentioned only Bt Batok branch this year. As for Maths Oasis, they dun hold AMC, they hold the other AMC, i.e. AMC 8, 10 & 12.

[empressplace]

MathsOlympiadtrainer:

the boxes are identical so the way to put 4 different marbles in 4 identical is only 1.

Thanks! Finally got it. I missed the key words. 4 different colours.

Is this not permutations and combinations taught in A levels in the past? What would be the workings if done in the permutations and combinations' way for exams?

[kiasiparent]

empressplace:

MathsOlympiadtrainer:

the boxes are identical so the way to put 4 different marbles in 4 identical is only 1.

Thanks! Finally got it. I missed the key words. 4 different colours.

Is this not permutations and combinations taught in A levels in the past? What would be the workings if done in the permutations and combinations' way for exams?

4C4 = 1
4C3 x 1C1 = 4 x 1 = 4 (because only 1 marble remains after you pick 3 marbles out)
4C2 x 2C2/2 = 6/2 = 3
4C2 = 6
1x1x1x1= 1

Total = 15

[kiasiparent]

quekcc:

trileets:

May I know how this qn is done?


Find the number of ways to put 4 different coloured marbles into 4 identical empty boxes.

Ans: 15 (my ans of 24 is wrong)



TIA

Your answer 24 is the number of ways to arrange 4 different coloured marbles in order. But the question is looking for number of ways to group the 4 different coloured marbles.

There are 5 possible ways of grouping.

1) all in 1 box - 1 possible combination only
2) 3 in 1 box and 1 in another box - 4 possible combinations
3) 2 in 1 box and 2 in another box - 6 possible combinations
4) 2 in 1 box, 1 in 2nd box and 1 in another box - 3 possible combinations
5) 1 in each box - 1 possible combination only

So total = 1 + 4 + 6 + 3 + 1 = 15

3) 2 in 1 box and 2 in another box - 3 possible combinations
4) 2 in 1 box, 1 in 2nd box and 1 in another box - 6 possible combinations