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# OCR (Non MEI) D2 Wednesday 25th May 2016 Watch

1. (Original post by btsx)
for the last question I only put the route but not the minimax value, is that ok?
almost certain they only asked for the route because i remember putting the value in brackets , someone correct me if i'm wrong
2. (Original post by Carter1)
aha I was not looking forward to that question, I was expecting another bird sanctuary or dog houses.... But yeh I know how you feel, I had C2 before that exam and started to get lazy in D2
i hope c2 went well for you

the bird sanctuary question is the worst d1 question i came across - i was mentally prepared for such a question ahahah
3. (Original post by Carter1)
At least I have another 3 weeks until I need to deal with the trauma of simplex....
d1 is so much harder than d2 im sweating just thinking about it

isnt it in two weeks for ocr????
4. Anyone know the mark breakdown for each question?

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5. Quite happy with that paper, although there weren't many worded answer questions? Makes me think boundaries will be higher...

So glad i did D2 before C2 though
6. Last year we had basically no simplex in D1 so you guys can have fun with that
7. (Original post by xsanda)
Xsanda’s solutions:

1) Matching
i) JF=3-ND=4
1:MA
2:-
3:JF
4:ND
5:JA
6:MJ
ii) SO=5-JA=2
1:MA 2:JA 3:JF 4:ND 5: SO 6:MJ
iii) 3=JF,4=ND,5=SO always
1:MJ 2:MA 3:JF 4:ND 5: SO 6:JA

2) Flow
i) FT = 2, DT = 4, cut = 9
iia) SCBFT +2 (given)
b) SCFBAEDT +1
iii) 8, with cut {SABCF}{DET} of value 8

3) Hungarian
i) Add dummy column X with 100 in each
Reduce rows -86, -91, -88, -98
Reduce cols -0,-2,-0,-2
ii) AS, BT, CL, no match for D, £271 cost
iii) CS, BT; AL costs £83

4) Rock paper scissors
i) scissors with paper: gain of 1, loss of 2: 1 + (-2) ≠ 0
ii) playsafe: scissors
iii) scissors 2-2p-4q, paper 3p+2q-2, rock 2q-p
iv) p=0.5, q=0.25, rock = 0.25

5) critical path analysis
i) F and H also critical
ii) A: -, B: -, C: -, D: A, E: BD, F: BCD, G: E, H: EF, I: GH, J: H
iii) 60 mins, critical ABDEHJ
iv) allocation for 3 people
v) allocation for 2 people
vi) A is critical, but so is B, which happens at the same time, so must reduce both to gain 5 minutes. 200+400=£600. Best is H and J: £500+£500 = £1000

6i) (0;0)-(1;1)-(2;1)-(3;0)-(4;0): weight 7
ii) 1 point
iii) (0;0)-(1;0) 1
(0;0)-(1;1) 2
(1;0)-(2;0) 1
(1;0)-(2;1) 1
(1;1)-(2;0) 2
(1;1)-(2;1) 1
(2;0)-(3;0) 0
(2;0)-(3;1) 0
(2;1)-(3;0) 2
(2;1)-(3;1) 0
(3;0)-(4;0) 1
(3;1)-(4;0) 2
iv) (0;0)-(1;0)-(2;0)-(3;0)-(4;0): 1 point per round maximum
All spot-on apart from the 2nd row in Q3(i) is reduced by 92, not 91.
8. (Original post by xsanda)
Xsanda’s solutions:

1) Matching
i) JF=3-ND=4
1:MA
2:-
3:JF
4:ND
5:JA
6:MJ
ii) SO=5-JA=2
1:MA 2:JA 3:JF 4:ND 5: SO 6:MJ
iii) 3=JF,4=ND,5=SO always
1:MJ 2:MA 3:JF 4:ND 5: SO 6:JA

2) Flow
i) FT = 2, DT = 4, cut = 9
iia) SCBFT +2 (given)
b) SCFBAEDT +1
iii) 8, with cut {SABCF}{DET} of value 8

3) Hungarian
i) Add dummy column X with 100 in each
Reduce rows -86, -92, -88, -98
Reduce cols -0,-2,-0,-2
ii) AS, BT, CL, no match for D, £271 cost
iii) CS, BT; AL costs £83

4) Rock paper scissors
i) scissors with paper: gain of 1, loss of 2: 1 + (-2) ≠ 0
ii) playsafe: scissors
iii) scissors 2-2p-4q, paper 3p+2q-2, rock 2q-p
iv) p=0.5, q=0.25, rock = 0.25

5) critical path analysis
i) F and H also critical
ii) A: -, B: -, C: -, D: A, E: BD, F: BCD, G: E, H: EF, I: GH, J: H
iii) 60 mins, critical ABDEHJ
iv) allocation for 3 people
v) allocation for 2 people
vi) A is critical, but so is B, which happens at the same time, so must reduce both to gain 5 minutes. 200+400=£600. Best is H and J: £500+£500 = £1000

6i) (0;0)-(1;1)-(2;1)-(3;0)-(4;0): weight 7
ii) 1 point
iii) (0;0)-(1;0) 1
(0;0)-(1;1) 2
(1;0)-(2;0) 1
(1;0)-(2;1) 1
(1;1)-(2;0) 2
(1;1)-(2;1) 1
(2;0)-(3;0) 0
(2;0)-(3;1) 0
(2;1)-(3;0) 2
(2;1)-(3;1) 0
(3;0)-(4;0) 1
(3;1)-(4;0) 2
iv) (0;0)-(1;0)-(2;0)-(3;0)-(4;0): 1 point per round maximum
Updated, thanks Mr M Jr
(Original post by Mr M (jr))
All spot-on apart from the 2nd row in Q3(i) is reduced by 92, not 91.
9. (Original post by xsanda)
Updated, thanks Mr M Jr
For the first part of 5vi, would it be sufficient to say "B is also critical so it also must be reduced, thus it will cost >£200"?
10. Hi bassala,
That's exactly right for the first part of the question, but for the second part, you need to find the total cost, as £1000
11. (Original post by xsanda)
Hi bassala,
That's exactly right for the first part of the question, but for the second part, you need to find the total cost, as £1000
Yep, I got that cheers
12. I got it all right except for 6iii where I messed up one of the weights and 6iv where I messed it up due to the previous question. Do you remember how many marks those two were worth? I really need 90 ums on this :x
13. (Original post by Mr M (jr))
All spot-on apart from the 2nd row in Q3(i) is reduced by 92, not 91.
I got it all right except for 6iii where I messed up one of the weights and 6iv where I messed it up due to the previous question. Do you remember how many marks those two were worth? I really need 90 ums on this, don't want to resit next year
14. (Original post by Mr M (jr))
All spot-on apart from the 2nd row in Q3(i) is reduced by 92, not 91.
hello, please could you estimate how many marks I'll lose for not making the negatives positive on the last - dynamic programming question? I got the correct route at the end and all the method should be right.... my table contains negatives though

i think i lost 3 marks excluding the final question, and am hoping this one mistake isn't detrimental and causes me to go below the 90 ums score.. :/
15. (Original post by duncanjgraham)
hello, please could you estimate how many marks I'll lose for not making the negatives positive on the last - dynamic programming question? I got the correct route at the end and all the method should be right.... my table contains negatives though

i think i lost 3 marks excluding the final question, and am hoping this one mistake isn't detrimental and causes me to go below the 90 ums score.. :/
Probably drop 2 marks
16. (Original post by Mr M (jr))
Probably drop 2 marks
17. 67/72 for 90 ums damn
18. Surprised the boundaries are so high for this. 62 for an A!
19. (Original post by marioman)
Surprised the boundaries are so high for this. 62 for an A!
so am I - the grade boundaries for fp2 and s2 are nice/normal but this is tbh significantly different to usual.
20. high garde boundaries in this let me down - if I'd got one more mark in this exam I'd have an A* in further maths but nah - A aldsfmsdlfkm

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