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.
-
Re: OCR Decision 1 - 24 May 2012they 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](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. -
Re: OCR Decision 1 - 24 May 2012Really? That would be so cool! Do you know the question number as well as the past paper year?(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. -
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
-
Re: OCR Decision 1 - 24 May 2012In that case it would be 62, really hope I get it, think I dropped like 6 marks(Original post by Nathdragon5)
I wonder what 100 UMS will be :P
-
Re: OCR Decision 1 - 24 May 2012I'd probably still get an E haha(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 -
Re: OCR Decision 1 - 24 May 2012Really? I think you're being tooambitious(Original post by tooambitious)
In that case it would be 62, really hope I get it, think I dropped like 6 marks
Just kidding XD, props to you if you truly think you only dropped 6 marks, that's crazy! -
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. -
Re: OCR Decision 1 - 24 May 2012Yeah, same here, that'd be amazing to get 100 when you know you screwed up(Original post by tooambitious)
In that case it would be 62, really hope I get it, think I dropped like 6 marks
well, best of luck to you!
-
Re: OCR Decision 1 - 24 May 2012Are you sure it asked answer in minutes??(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.Last edited by sbchan0628; 24-05-2012 at 12:27. -
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) UnsureLast edited by FK_; 24-05-2012 at 12:40. -
Re: OCR Decision 1 - 24 May 2012I see what you did there(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!
, 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
-
Re: OCR Decision 1 - 24 May 2012yeah, 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(Original post by sbchan0628)
Are you sure it asked answer in minutes?? -
Re: OCR Decision 1 - 24 May 2012This.(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
-
Re: OCR Decision 1 - 24 May 2012**** YES(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

, 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