Tuesday, 30 May 2017

SMO 2017 (Senior Section) Answers

SMO 2017 Senior Round 2 List

Cut off for Rd 2 ~?

SMO 2017 Senior Round 1 Questions

You can find past year SMO papers (2005-2013, Round 1 and 2 with full solutions) here.

For more SMO Senior Special Round practice, you may download the All Soviet Union Math Competition 1961-1987 here (note that only the first 99 questions have solutions included).

SMO 2017 (Senior Section) Answers

1. D
2. D
3. C
4. B
5. B
6. C
7. A
8. C
9. E
10. A
11. 630
12. 6
13. 9
14. 24
15. 816
16. 100
17. 505
18. 25260
19. 777
20. 121
21. 7
22. 216
23. 487
24. 2685 (*amended)
25. 48
26. 372 (*amended)
27. 6
28. 30
29. 8 (*amended)
30. 38
31. 2590
32. 47
33. 126
34. 24
35. 200

60 comments:

Unknown said...

qn7 should be A?

Anonymous said...

Is Q7 A, because sqrt(sin^2 a) = -sina in this case since sin a is negative?

Anonymous said...

For q27, wouldn't m=6, n=1 be a possible solution set?

Xiaoying Yan said...
This comment has been removed by the author.
Anonymous said...

777

Anonymous said...

26 should be 1419

Anonymous said...

Is getting 17 a good thing

Anonymous said...

also 17

Anonymous said...

is qn 31 answer missing a last digit

Anonymous said...

Isn't q13 9?
And

Anonymous said...

Anyone has the questions

Anonymous said...

Hello, I think the answer to Question 13 should be 9, and the answer to question
31 should be 2590

Anonymous said...

13 cannot be 1

Anonymous said...

Q13 cannot be 1 cuz tanA-1 is not equal 0 right?

Shouldn't it be 9

Anonymous said...

Did y'all find this harder or easier than last year's paper?

Anonymous said...

Shouldn't Q18 be 25260? Thanks

Anonymous said...

is 29 9 or 4?

Anonymous said...

@Anonymous How did you find it?

Anonymous said...

@Anonymous

5*9C4*5C2 + 5C2*9C3*4C1*5C1 + 5C3*9C2*4C2 = 25260

Anonymous said...

Is this year's paper easier or harder than last year's? And does anyone have the question paper?

Anonymous said...

13 should be 4. I think you multiplied by two instead of dividing

Anonymous said...

I got 15, would I get into round 2

Anonymous said...

Not a high chance, but still possible

Anonymous said...

what about 17?

Anonymous said...

I got 14 because I made some really stupid mistakes (like writing 7^3 = 2301 instead of 2401 and thus getting 387 instead of 487). Is that a silver though? Probably not round 2 right?

PS. 17 should get you into round 2

Anonymous said...

Anyone knows what was last year cutoff point

Anonymous said...

I think it was 18-19. So this year should be lower cuz it's harder right?

Anonymous said...

Can you upload the questions? Thank you!

Anonymous said...

how about 16?

Anonymous said...

when and how r we gonna know the cutoff point this year?

Anonymous said...

Shouldn't q28 be 36? AF is 1/6 of AC, so 6AC/AF should be 36.

Anonymous said...

I think q26 is 372 because moving between cells not on the lines

Anonymous said...

I got 16, can I get into round 2?

Russell Saerang said...

Qn 24 should be 2685?

Anonymous said...

@Anonymous I found it harder, and probably did worse than last year as I made many careless mistakes :( but a number of people I knew found it easier

Anonymous said...

is 11 good enough to get silver? screwed up too many questions :((

Anonymous said...

Isn't qns 25 42? Assuming you have the worst luck and get 20+18=38, now you have two pairs of the same colour. Then you take one each from the remaining 3 colours 38+3=41.Take one more and you'll have 3 pairs of the same colour 41+1=42.

Anonymous said...

My answer also 42.

Anonymous said...

Mine is also 42

Anonymous said...

Same! Mine is also 42. How to get 48?

Anonymous said...

Worst case scenario is when you take 20+18 and then you take 3 of each other sock, so you don't have 3 complete pairs yet. Then the next sock will complete the last pair. Thus 20+18+3+3+3+1=48.

Anonymous said...

Omg thanks!! But shit, I forgot that it was in pairs

Unknown said...

I also thought so at first. But if you read the question carefully it asks you to move from cell to cell and NOT along the grid lines.

Anonymous said...

Do you think a 17 can get me into round 2?

Anonymous said...

I got 3 qns wrong because of wrong mental calculations :(. Can anyone tell me what I might get for 12 correct.

Anonymous said...

How much for bronze?

Anonymous said...

As requested, for question 28, note that since AP = PB and other reasons, triangles EAP and QBP are congruent such that EA = BQ. Furthermore, triangles EAF and QCF are similar.

The ratio AF / FC = EA / CQ = 3 / (3+9) = 1/4. Hence, AC / AF = 5, giving rise to the final answer of 30.

Anonymous said...

When will we get the results?

Manikandan Praveen Kannappan said...

What are the cut off's for honourable mention, bronze, silver, gold?

Manikandan Praveen Kannappan said...

What are the cut off's for honourable mention, bronze, silver, gold?

Anonymous said...

Has anyone received notification about round 2

Anonymous said...

It is already out.

http://sms.math.nus.edu.sg/Competitions/CompetitionHomePage.aspx#round2

Just curious, anyone has a rough idea what is cutoff?

Anonymous said...

cut off is the point you need to get for round 2

Anonymous said...

@the guy above the last one do you mean what is the cut-off grade? I mean i got 20 and got through, not sure if that is considered low

Anonymous said...

Hi what's the score to get honourable mention?

Anonymous said...

Hi. Can anyone tell me what I might get for getting 12 qn correct?

Skittles Pony said...

Hi, for question 29, I suspect the answer is 9.

If n = 8, then 9^256 > 9^256 - 4^256 =
(3^256+2^256)(3^256-2^256) = (3^256+2^256)(3^128+2^128)(3^128-2^128)=...=5(3^2+2^2)...(3^256+2^256)

I could be wrong. Help me check

Anonymous said...

anyone know how much is roughly needed for silver? thanks

Anonymous said...

I think it's around 11.

Sindhuja said...

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