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
at

61 comments:

  1. Unknown30 May 2017 at 15:11

    qn7 should be A?

    ReplyDelete
  2. Anonymous30 May 2017 at 15:13

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

    ReplyDelete
  3. Anonymous30 May 2017 at 15:13

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

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  4. Unknown30 May 2017 at 15:15

    This comment has been removed by the author.

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  5. Anonymous30 May 2017 at 15:16

    777

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  6. Anonymous30 May 2017 at 15:18

    26 should be 1419

    ReplyDelete
    Replies
    1. Unknown31 May 2017 at 15:44

      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.

      Delete
  7. Anonymous30 May 2017 at 15:20

    Is getting 17 a good thing

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  8. Anonymous30 May 2017 at 15:29

    is qn 31 answer missing a last digit

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  9. Anonymous30 May 2017 at 15:29

    Isn't q13 9?
    And

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  10. Anonymous30 May 2017 at 15:30

    Anyone has the questions

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  11. Anonymous30 May 2017 at 15:31

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

    ReplyDelete
  12. Anonymous30 May 2017 at 15:34

    13 cannot be 1

    ReplyDelete
  13. Anonymous30 May 2017 at 15:36

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

    Shouldn't it be 9

    ReplyDelete
  14. Anonymous30 May 2017 at 15:36

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

    ReplyDelete
  15. Anonymous30 May 2017 at 15:37

    Shouldn't Q18 be 25260? Thanks

    ReplyDelete
  16. Anonymous30 May 2017 at 15:39

    is 29 9 or 4?

    ReplyDelete
  17. Anonymous30 May 2017 at 15:39

    @Anonymous How did you find it?

    ReplyDelete
  18. Anonymous30 May 2017 at 15:43

    @Anonymous

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

    ReplyDelete
  19. Anonymous30 May 2017 at 15:48

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

    ReplyDelete
  20. Anonymous30 May 2017 at 16:14

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

    ReplyDelete
  21. Anonymous30 May 2017 at 16:17

    I got 15, would I get into round 2

    ReplyDelete
    Replies
    1. Anonymous30 May 2017 at 16:36

      Not a high chance, but still possible

      Delete
  22. Anonymous30 May 2017 at 16:49

    what about 17？

    ReplyDelete
  23. Anonymous30 May 2017 at 17:20

    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

    ReplyDelete
  24. Anonymous30 May 2017 at 17:23

    Anyone knows what was last year cutoff point

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  25. Anonymous30 May 2017 at 17:29

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

    ReplyDelete
  26. Anonymous30 May 2017 at 17:34

    Can you upload the questions? Thank you!

    ReplyDelete
  27. Anonymous30 May 2017 at 17:51

    how about 16?

    ReplyDelete
  28. Anonymous30 May 2017 at 17:54

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

    ReplyDelete
  29. Anonymous30 May 2017 at 19:15

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

    ReplyDelete
  30. Anonymous30 May 2017 at 19:26

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

    ReplyDelete
  31. Anonymous30 May 2017 at 22:00

    I got 16, can I get into round 2?

    ReplyDelete
  32. Unknown30 May 2017 at 22:11

    Qn 24 should be 2685?

    ReplyDelete
  33. Anonymous30 May 2017 at 22:25

    @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

    ReplyDelete
  34. Anonymous31 May 2017 at 00:58

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

    ReplyDelete
  35. Anonymous31 May 2017 at 07:17

    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.

    ReplyDelete
  36. Anonymous31 May 2017 at 07:28

    My answer also 42.

    ReplyDelete
  37. Anonymous31 May 2017 at 09:21

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

    ReplyDelete
  38. Anonymous31 May 2017 at 12:31

    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.

    ReplyDelete
  39. Anonymous31 May 2017 at 12:49

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

    ReplyDelete
  40. Anonymous31 May 2017 at 18:24

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

    ReplyDelete
  41. Anonymous31 May 2017 at 20:28

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

    ReplyDelete
  42. Anonymous31 May 2017 at 21:41

    How much for bronze?

    ReplyDelete
  43. Anonymous1 June 2017 at 22:17

    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.

    ReplyDelete
  44. Anonymous2 June 2017 at 19:46

    When will we get the results?

    ReplyDelete
  45. Praveen5 June 2017 at 19:47

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

    ReplyDelete
  46. Praveen5 June 2017 at 19:47

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

    ReplyDelete
  47. Anonymous12 June 2017 at 16:41

    Has anyone received notification about round 2

    ReplyDelete
  48. Anonymous12 June 2017 at 20:55

    It is already out.

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

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

    ReplyDelete
  49. Anonymous13 June 2017 at 11:08

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

    ReplyDelete
  50. Anonymous13 June 2017 at 19:04

    @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

    ReplyDelete
  51. Anonymous13 June 2017 at 21:09

    Hi what's the score to get honourable mention?

    ReplyDelete
  52. Anonymous17 June 2017 at 16:46

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

    ReplyDelete
  53. Skittles Pony19 June 2017 at 12:02

    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

    ReplyDelete
  54. Anonymous21 June 2017 at 21:46

    anyone know how much is roughly needed for silver? thanks

    ReplyDelete
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    ReplyDelete