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Arsey's D1 Edexcel Summer 2013 Model Solutions BOTH PAPERS Watch

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    Fairly reasonable paper I thought


    1. Matchings - pretty simple, although not breaking down the 2 required paths into separate part of the question, could cause problems.


    2. Quick sort and Bin packing - very easy, I thought it was odd how the first-fit decreasing didn't reduce the number of bins though


    3. Prim's and Kruskal's - very easy


    4. Dikky - harder than normal due to the sneaky part of the route. Quite easy to mank up b) too.


    5. Postie - standard. A common error on c) will be to repeat DE.


    6. LP - not easy but it never is. Part b) will be a bloodbath.


    alt to part b)


    no more than 1.5 times as many small as large


    for every 3 small you need at least 2 big




    7. CPA - Fairly standard but the backward scans not using the dummy paths will be a very common error. Gantt chart took too long. f) and g) will be poorly answered.



    Overall I would say it was a little easier than Jan, I would expect it to be around 63 for an A.


    This summer I will upload solutions to the following Edexcel papers:

    Core 1;
    Core 2;
    Core 3;
    Core 4;
    FP1;
    M1;
    M2;
    S1;
    D1;
    D2.

    I will try to get hold of some solutions for FP2; FP3 and M3.

    I don't do S2

    All papers will be uploaded in line with site rules (please don't PM me asking when I will I be uploading them).

    I have uploaded my solutions to the other time zone paper, which I thought was a bit harder.
    Attached Images
  1. File Type: pdf 13 May D1 Int Model red.pdf (556.2 KB, 3271 views)
  2. File Type: pdf 13 May D1 Model red tsr .pdf (563.6 KB, 8337 views)
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    Gantt chart took WAY too long. I ran out of time by a few seconds...
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    YES T in Q4 WAS 30! All my other friends said it was 31 and said I got it wrong XD. Overall nice paper, I did make some mistakes with bin-packing and I didn't have time to finish the last question last part and finish the gantt chart. If all goes well I should get around 68 .
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    when will the S1 solutions be up?
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    did you have to draw the objective line?
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    (Original post by Arsey)
    Fairly reasonable paper I thought


    1. Matchings - pretty simple, although not breaking down the 2 required paths into separate part of the question, could cause problems.


    2. Quick sort and Bin packing - very easy, I thought it was odd how the first-fit decreasing didn't reduce the number of bins though


    3. Prim's and Kruskal's - very easy


    4. Dikky - harder than normal due to the sneaky part of the route. Quite easy to mank up b) too.


    5. Postie - standard. A common error on c) will be to repeat DE.


    6. LP - not easy but it never is. Part b) will be a bloodbath.


    alt to part b)


    no more than 1.5 times as many small as large


    for every 3 small you need at least 2 big




    7. CPA - Fairly standard but the backward scans not using the dummy paths will be a very common error. Gantt chart took too long. f) and g) will be poorly answered.



    Overall I would say it was a little easier than Jan, I would expect it to be around 63 for an A.
    quick question Arsey for the mathcing,I have 2 alternating paths with change status and complete matching ?thats fine right?

    the route insepction i said repeat arc BD(38) as it is smallest and so you start at E and end at A,and put 344+48

    IS THAT FINE
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    (Original post by Parrallax)
    when will the S1 solutions be up?
    already up
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    (Original post by otrivine)
    quick question Arsey for the mathcing,I have 2 alternating paths with change status and complete matching ?thats fine right?

    the route insepction i said repeat arc BD(38) as it is smallest and so you start at E and end at A,and put 344+48

    IS THAT FINE
    yes, although you were required to state your improved matching.

    yes
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    (Original post by Arsey)
    Fairly reasonable paper I thought


    1. Matchings - pretty simple, although not breaking down the 2 required paths into separate part of the question, could cause problems.


    2. Quick sort and Bin packing - very easy, I thought it was odd how the first-fit decreasing didn't reduce the number of bins though


    3. Prim's and Kruskal's - very easy


    4. Dikky - harder than normal due to the sneaky part of the route. Quite easy to mank up b) too.


    5. Postie - standard. A common error on c) will be to repeat DE.


    6. LP - not easy but it never is. Part b) will be a bloodbath.


    alt to part b)


    no more than 1.5 times as many small as large


    for every 3 small you need at least 2 big




    7. CPA - Fairly standard but the backward scans not using the dummy paths will be a very common error. Gantt chart took too long. f) and g) will be poorly answered.



    Overall I would say it was a little easier than Jan, I would expect it to be around 63 for an A.


    This summer I will upload solutions to the following Edexcel papers:

    Core 1;
    Core 2;
    Core 3;
    Core 4;
    FP1;
    M1;
    M2;
    S1;
    D1;
    D2.

    I will try to get hold of some solutions for FP2; FP3 and M3.

    I don't do S2

    All papers will be uploaded in line with site rules (please don't PM me asking when I will I be uploading them).
    Thanks, i think i lost i got about 65, hopefully an A
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    (Original post by Arun1323)
    did you have to draw the objective line?
    Yup and you have to write that the line is your objective line otherwise I think you lose a mark. Also explaining the 2nd part of the linear programming I said that for every 2* 2 seater boats there should be atleast 3*(4 seater boats) is that still correct?
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    Almost identical. Lost out on three marks I see, but yes, 72/75. Hoping for 95 uMS?

    tOBY
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    (Original post by Arsey)
    yes, although you were required to state your improved matching.

    yes
    when you say improved matching do u mean to show in the graph? cause in the solution u put the improved mathcing in the diagram? how many marks would u lose for that thanks sir


    Sir the question on 2x<3y i said the number of 2 seater cars must be at least 3/2 more as the number of 4 seater cars
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    i think the grade boundaries will be very narrow.

    there is enough tricky stuff that very few people will get full marks but lots of easy stuff so very few will have bombed out.

    I think it could be as high as 40 for an E.
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    Any idea of marks lost for correct answer for 3a but with distance matrix defaced (no correct labelling or anything) and x and y found for 6d but min cost not stated?
    Thanks
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    (Original post by tobywalsh)
    Almost identical. Lost out on three marks I see, but yes, 72/75. Hoping for 95 uMS?

    tOBY
    Nice, I think I could have done better, I was just scared as I thought my pencil wouldn't go through so I went over everything with pen. Yes I know I'm an idiot XD.
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    (Original post by otrivine)
    when you say improved matching do u mean to show in the graph? cause in the solution u put the improved mathcing in the diagram? how many marks would u lose for that thanks sir
    you can either list the improved matching, or draw it. I encourage drawing as it helps you to spot silly errors.
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    I said 2 seated boats at most 1.5 times no of 4 seated boats

    As for CA, If I wrote the justification correctly for last part but still had wrong bounds ( cascade still more than lower bound) will I get any marks for last part?
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    (Original post by Arsey)
    already up
    where are the s1 answers? i can't find them if they are already up
 
 
 
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