OCR Decision 1 - 24 May 2012

Maths exam discussion - share revision tips in preparation for GCSE, A Level and other maths exams and discuss how they went afterwards.

Announcements Posted on
TSR launches Learn Together! - Our new subscription to help improve your learning 16-05-2013
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
Sign in to Reply
  1. Bless3d's Avatar
    • Junior Member
    • Posts: 27
    Re: OCR Decision 1 - 24 May 2012
    (Original post by icy elemental)
    You can't use this as an example because there was an impossible question that year which they disregarded when working out marks.
    they didn't disregard it. As long as you got to the correct answer, you got full marks regardless of what fudging you tried to do afterwards [to get to their answer]
  2. kofanov's Avatar
    • New Member
    • Posts: 22
    Re: OCR Decision 1 - 24 May 2012
    (Original post by icy elemental)
    You can't use this as an example because there was an impossible question that year which they disregarded when working out marks.
    Really? That would be so cool! Do you know the question number as well as the past paper year?
  3. kofanov's Avatar
    • New Member
    • Posts: 22
    Re: OCR Decision 1 - 24 May 2012
    how many marks is question 1, 2 and 3 all together??
  4. Nathdragon5's Avatar
    • Respected Member
    • Location: Purley
    • Posts: 176
    Re: OCR Decision 1 - 24 May 2012
    If anyone wants to take the time now to try and write out an unofficial mark scheme, that'd be very helpful, but I've got Physics tomorrow, I'll write it up after that! Don't worry about it guys, at least the general consensus is that it was hard. UMS will be low, you can pull up your average with other stuff

    Good luck with all your other exams
  5. tooambitious's Avatar
    • TSR Demigod
    • Posts: 5,619
    Re: OCR Decision 1 - 24 May 2012
    (Original post by Nathdragon5)
    I wonder what 100 UMS will be :P
    In that case it would be 62, really hope I get it, think I dropped like 6 marks
  6. kofanov's Avatar
    • New Member
    • Posts: 22
    Re: OCR Decision 1 - 24 May 2012
    does anyone knowhow many marks was question one, two and three all together?
  7. Ursin's Avatar
    • Adored and Respected Member
    • Posts: 412
    Re: OCR Decision 1 - 24 May 2012
    (Original post by Lucozad)
    I atleast want a B this year. No chance for an A now, unless the grade boundaries are like this :

    A - 22
    B - 17
    C - 12
    D - 7
    E - 2
    U - 0
    I'd probably still get an E haha
  8. BobGreggary's Avatar
    • Junior Member
    • Posts: 55
    Re: OCR Decision 1 - 24 May 2012
    (Original post by tooambitious)
    In that case it would be 62, really hope I get it, think I dropped like 6 marks
    Really? I think you're being tooambitious

    Just kidding XD, props to you if you truly think you only dropped 6 marks, that's crazy!
  9. samjj8's Avatar
    • Respected Member
    • Posts: 233
    Re: OCR Decision 1 - 24 May 2012
    I felt ill for the for 20 minutes. Couldn't concentrate, had to rush through everything, had to leave the room, came back felt OK afterwards, was able to do the first question at the end, didn't finish the paper, and missed loads of bits out.
    The simplex was a complete joke for the amount of marks it was for.
    Need to get 100% on all other modules now. :\
    Last edited by samjj8; 24-05-2012 at 12:25.
  10. Nathdragon5's Avatar
    • Respected Member
    • Location: Purley
    • Posts: 176
    Re: OCR Decision 1 - 24 May 2012
    (Original post by tooambitious)
    In that case it would be 62, really hope I get it, think I dropped like 6 marks
    Yeah, same here, that'd be amazing to get 100 when you know you screwed up well, best of luck to you!
  11. sbchan0628's Avatar
    • New Member
    • Posts: 8
    Re: OCR Decision 1 - 24 May 2012
    (Original post by icy elemental)
    Question 1 involved joining up places with arcs, then using Dijkstra's algorithm to work out the shortest length from A to F. Shortest length was 49, and went AEF. A to E was 18, E to F was 31.
    Last part was 1200 seconds but it asked for it in minutes so 20 minutes.
    Are you sure it asked answer in minutes??
    Last edited by sbchan0628; 24-05-2012 at 12:27.
  12. icy elemental's Avatar
    • Full Member
    • Posts: 113
    Re: OCR Decision 1 - 24 May 2012
    100% certain
  13. FK_'s Avatar
    • Junior Member
    • Posts: 47
    Re: OCR Decision 1 - 24 May 2012
    1i) Draw the diagram with 10 arcs
    1ii) Complete Dijkstra's algorithm. Length = 49 Route : AEF
    1ii) Time = 1200 seconds

    2i) Draw a pentagon (eulerian with 5 arcs)
    ii) 5 arcs, 5 vertices, semi-eulerian, one vertex with order 4 - hence join the vertices with order 1 together
    iii) 5 arcs, 5 vertices, semi-eulerian (none order of 4).

    3i) Connect up the subjects
    3ii) The two odd nodes, D1 and M2 had to be in separate sessions. For the rest, you had to just following the arcs through.
    iii) An arc is added between M1 D1 which forms a loop of 3 arcs. Explain logically why this is impossible.

    4i) Simplex Question: add 'slack variables' and make equations with equals signs. The restrictions on s,t and u were that they had to be greater than or equal to 0
    ii) iii)... Answer was 26.4
    Slack for S was 2, hence there is 2 left other in constraint 1 (or something to that effect).

    5i) Linear programming question - find equations of the lines
    ii)Find optimal point
    x=4/3
    y=8/3
    iii) Integer solution: x=2 and y=2 which gives a value of 12? for P...

    5i) Can't remember. Find lower bound and upper bound etc.

    6i) X=-0.2
    ii) X decreases by 1 and goes back to X=0
    iii) The algorithm gives the same root as in part i but with more decimal places and ridiculous fractions (what is the point in that question?)
    iv) Unsure
    Last edited by FK_; 24-05-2012 at 12:40.
  14. tooambitious's Avatar
    • TSR Demigod
    • Posts: 5,619
    Re: OCR Decision 1 - 24 May 2012
    (Original post by BobGreggary)
    Really? I think you're being tooambitious

    Just kidding XD, props to you if you truly think you only dropped 6 marks, that's crazy!
    I see what you did there , to work out 100 you do A +2*(A-B), yeah I spent like 1 hour on the first 5 qs, because I expected time pressure so I rushed, then 30 mins on the last q, which I kept on misreading :facepalm:
  15. kofanov's Avatar
    • New Member
    • Posts: 22
    Re: OCR Decision 1 - 24 May 2012
    (Original post by sbchan0628)
    Are you sure it asked answer in minutes??
    yeah, the part three with seconds and the n^2, how did you calculate that? as far as I remember I put something like 3 x (1200/400)^2
  16. icy elemental's Avatar
    • Full Member
    • Posts: 113
    Re: OCR Decision 1 - 24 May 2012
    Well, 99% certain anyway :L
  17. kofanov's Avatar
    • New Member
    • Posts: 22
    Re: OCR Decision 1 - 24 May 2012
    ANYONE!! how many marks total for first three questions was there???
  18. icy elemental's Avatar
    • Full Member
    • Posts: 113
    Re: OCR Decision 1 - 24 May 2012
    t^2 is proportional to S.
    S is multiplied by 20. Therefore t is multiplied by 20^2 or 400.
    3 x 400 = 1200 seconds
    = 20 minutes
  19. Nathdragon5's Avatar
    • Respected Member
    • Location: Purley
    • Posts: 176
    Re: OCR Decision 1 - 24 May 2012
    (Original post by FK_)
    iv) The algorithm has no counter. Hence, if the cubic has no real roots, the algorithm will go into an infinite loop
    This.
  20. kofanov's Avatar
    • New Member
    • Posts: 22
    Re: OCR Decision 1 - 24 May 2012
    (Original post by icy elemental)
    t^2 is proportional to S.
    S is multiplied by 20. Therefore t is multiplied by 20^2 or 400.
    3 x 400 = 1200 seconds
    = 20 minutes
    **** YES
Sign in to Reply
Share this discussion:  
Article updates
Moderators

We have a brilliant team of more than 60 volunteers looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Reputation gems:
The Reputation gems seen here indicate how well reputed the user is, red gem indicate negative reputation and green indicates a good rep.
Post rating score:
These scores show if a post has been positively or negatively rated by our members.