SMO 2014 Junior Round 2 Questions

SMO 2014 (Junior Section) Answers

1. C

2. D

3. E

4. A

5. D

6. E

7. A

8. C

9. D

10. E

11. 28

12. 21

13. 60

14. 935

15. 16

16. 2017

17. 8

18. 491

19. 52

20. 4008

21. 10

22. 24

23. 2

24. 25

25. 22

26. 0 (question is wrong as x is not real!)

27. 2

28. 2500

29. 2809

30. 203

31. 5956

32. 1

33. 44

34. 144

35. 4

Initial answers are provided by a Year 1 NUS High student who does not wish to be named.

**SMO (Junior) Previous Years' Cut-off Points (Inclusive of Round 2 scores)**

2013 Gold (27), Silver (11), Bronze (8), HM (7), Round 2 (13), Top 30 (~50)

2012 Gold (17), Silver (8), Bronze (6), HM (5), Round 2 (8)

2011 Gold (12), Silver (9), Bronze (7), HM (6), Round 2 (11), Top 30 (~34)

2010 Gold (24), Silver (9), Bronze (8), HM (5)

2009 Gold (11), Silver (7), Bronze (6), HM (5)

2008 Gold (23), Silver (14), Bronze (11), HM (10)

2007 Gold (20), Silver (14), Bronze (11), HM (10)

## 36 comments:

thank you very much. You are so helpful

from leopard

the answer for question 26 is deffinitelly 0, no need double-check.

花豹

For Q26, try to find a real value for x.

The qn is wrong.

Seems to me that this year's paper is easier.

Qn 13, 14 , 17 workings to share??

There were some killer questions in this year's Junior paper

For qn 13, let (x-7)/(x-8) be 1-1/(x-8) and do the same for the rest. You will be left with 1/(x-9) - 1/(x-8) = 1/(x-12) - 1/(x-11) then just solve the equation to get x=10.

For qn 17, you will see that the two smallest positive divisors are 1 and 5 (to get 5, we have 6-1 since 1 is definitely the smallest divisor of N). Similarly we are sure that the largest divisor is N itself. The second largest divisor is simply N/5. Therefore, 1122=N+1/5N. Thus, n =935

Thx for replying melo

Hi Melo, I think your ans for Qn 17 is meant for Qn14? So may I know the workings for Qn 17 Thanks.

Hi, what do you predict the round 2 cut off point for this year to be?

Hi, I also want to know the cut-off points for all levels, can Jeck you tell us pls? when can we know?

Hey guys, the results for second round will be out soon, perhaps in another 2 weeks time. Be patient. :)

But the 2nd round is on the 28th so usually they should let the school know by this week rite so that the students can prepare ?

Not necessarily. They sometimes (or usually) release results one week before the second round.

@melo, sometimes they release on 15th , haish...wonder what is the cut off point this time lol for all levels?

I am guessing for senior will be around, if not more than 15, and for open will be around 14 (or more) :)

junior?

Not too sure... Havent taken the paper so not too sure abt the average score... Maybe more than 15 definitely?

Which junior paper did you guys think was harder? 2013 or 2014?

It can only be easy to some students who have high calibre or special training. It has never been easy for all years.

As in in comparison.

I'm not too sure about Junior but I know that Senior is much easier than last year. Last year's paper was a killer. I have looked through this year's Junior and it seems quite easy, but I haven't seen last year's so can't really make a comparison.

It was hard lol for junior...I think I couldnt make it to 2nd round...so sad.

don't be sad lol.... u still have many years to try SMO :p

I got 12 or 13 ( I'm not so sure because I guessed 2 MCQ) but didn't make it . I've got a friend who got 14 but made it into the second round . so I'm guessing cut off point is either 13 or 14 . note that I'm referring to the SMO Junior by this. And for open , I think it's between 9 and 11(according to my senior )

No. Open is 14 marks.

What is the cut off point for junior?

The cut-off point for SMO Junior should be 14 then since I got 13 and did not make it into the 2nd round and Anonymous mentioned that he had a friend who made it into the 2nd round with 14.

How to know how much the student got? Where to get this information? Thanks in advance!

round 2 qn 5,

In an 8x8 grid,n disks, numbered 1 to n are stacked, with random order, in a pile in the bottom left corner. The disks can be moved one at a time to a neighbouring cell either to the right or top. The aim to move all the disks to the cell at the top right corner and stack them in the order 1,2...,n from the bottom. Each cell, except the bottom left and top right cell, can hv at most one disk at any given time. Find the largest value of n so that the aim can be achieved.

can someone help to answer? Thanks.

I solved the question like this: Move the disks into the following formation. In this formation, no matter where disk 1 or 2 or any other disk is, there is always a pathway to the top right square. Take 'x' to be a disk, 0 to be an empty square.

xooooooo

xoxoxoxo

xoxoxoxo

xoxoxoxo

xoxoxoxo

xoxoxoxo

xoxoxoxo

xoxoxoxo

So the total number of disks is 8+7+7+7=

29How to do q4 of round 2

Can u help crack 7th Qn in SMO Junior Round 1 2014

The 7th problem is

TERRIBLE

+ NUMBER

-----------------

THIRTEEN

------------------

For question 7, we have:

L = 9

U = 0 ( => I >=1)

E + 1 = H

Suppose R <= 7

R + N = 10 + I, because I > 0 therefore N >= 4

E + R = N, therefore E >=7

B + B + 1 = 10 + E --> B >=8, --> B = 8 (because L already = 9)

Because B = 8 --> E = 7 (8 + 8 + 1 = 17)

Because H = E + 1 --> H = 7 + 1 = 8 what is impossible because B already = 8.

Therefore R = 8

R + N = 10 + I --> N >= 3

E + R = 10 + N --> E >= 5

B + B + 1 = 10 + E --> B >=7, because R = 8, L = 9 then B = 7 and E = 5

E + 1 = H --> H = 6

E + R = 10 + N --> N =3

N + N = 10 + I --> I = 1

At this moment we have only two values (2 and 4) for M and T , and M = 2, T = 4

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