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Another Impossible D1 Paper? [Edexcel] watch

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    Just did D1.
    There was a question, draw the activity network. Then part b was explain why you need 2 dummy activities.
    Well i drew it, checked it, double checked it and i only needed 1.
    Anyone else get that?
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    (Original post by Syncman)
    Just did D1.
    There was a question, draw the activity network. Then part b was explain why you need 2 dummy activities.
    Well i drew it, checked it, double checked it and i only needed 1.
    Anyone else get that?

    One of activity M or N needed a dummy to the end node.
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    yea i rememba that 1, totaly messed it up...i thought u needed 3 dummies at first??????? obviously not. and wot the hek was up wiv da last question ??? i wud hav been
    ok if they ddnt label it 4 u but then i got really confused... overall i wud be really surprised if i got over 50%, i h8 D1 its about a million times harder to understand from the book then D2. i'm just happy that'll i'll neva hav to do this totally random form of maths again....

    btw does the number 99 sound familiar 2 n e one???
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    I had 2 dummies, one from G and other one from M and N, meh...

    I hate D1 also, I find it the worst module to work on, I'd rather do S1 instead. There goes my A for A2 maths. Wonder what LSE says to this.
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    Well i completely messed up! I skipped a few questions do the simplex, spend ages tryin to do it then realised how little time i had left so went back but ran out of time to do the dykstra question so im gutted because ive lost simple marks! I literally must have got about 50%. Im gonna revise for monday and fingers crossed my mark from jan plus that will some how drag up my grade!

    Did anyone get -1/5 for the pivot at any point in the simplex and what was your maximum flow in the last question?
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    A lot of ppl mess up D1. For jan 05 paper 50/75 was an A
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    9100 or summin like that for profit for part c i think.
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    I just took it too, I thought it was an absolutely ridiculous paper. I can see a tiny bit of sense in making a paper "tricky", but making it too long AND tricky makes it impossible for people to achieve what they really can =(

    I'm fairly certain that the pivot on the simplex table was 0.4. The rule goes that you have to take the lowest POSITIVE solution to the final column divided by the pivotal column, I think you took the lowest overall.

    Anyway, I'm off to sulk =(

    Martin
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    (Original post by riks2004)
    9100 or summin like that for profit for part c i think.
    Yep yep, that's what I got. Woo =)

    Martin
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    Oh, that reminds me, did anyone find the maximum flow in the last question? Was it 11 more than the flow already shown? I think I did the working alright, but I managed to make a diagram where the sources put out more than the sinks took in =/

    Gah, down with anarchy =(

    Martin
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    It was an utter trainwreck. I shall keep my C from January I think!!
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    yea I got 9100 aswell. 0.4 seems familiar as well although mayb that was jst becos it was in R1 when you divide by 10 *shrugs*
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    (Original post by pumpkinstein)
    Oh, that reminds me, did anyone find the maximum flow in the last question? Was it 11 more than the flow already shown? I think I did the working alright, but I managed to make a diagram where the sources put out more than the sinks took in =/

    Gah, down with anarchy =(

    Martin
    The flows in were different but thats not surprising. Just means that not everything can flow through the network. That was the ONLY D1 paper that I have run out of time in (found the min cut and didnt have time to write it, paper was taken away )

    Everyone who took it hated it. Was just too long.

    I only got one dummy, the thing about M and N didnt make sense. I just drew two arcs to the end (right next to eachother).

    Although, they do adjust the marks so the grade boundires will probably be extra low. They better be because I need a B in this paper and have no way of draggin it up from other modules
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    hmmmm that kinda makes sense. a dummy from N or M to end. But i dont 100% see why. Whats wrong with 2 arcs both leaving the same point and ariving at same point?

    Apart from that and doing the sort 3 different way hence not managing to do last 4-5 marks. i think it went good. I think i prob dropped maybe 15 marks. But from the sounds of things that might just be 100UMS
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    wat did u get for djistra question? 53 for 1st bit then 54 for 2nd or summin like that, mite hav bin 43 n 44 but i kno it was def 1 of the two combinations that i got.
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    yep 53 n 54
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    gd gd
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    (Original post by riks2004)
    wat did u get for djistra question? 53 for 1st bit then 54 for 2nd or summin like that, mite hav bin 43 n 44 but i kno it was def 1 of the two combinations that i got.
    Got that, 53 and 54. The second bit was a joke really. Had to try and explain how CF is 1 longer then CEF which makes same journey without E the shortest route. Was not spending ages on that figuring out a totally different part!

    Alot of it was just time wasting. You had to find 2 alternating paths for one question. No need for that, it didnt test any knowledge finding the second one, just took up time that no one had to spare!

    Also, the last questions on the simplex thing didnt make much sense. Didnt know what to put to prove that it was not optimal
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    (Original post by Womble548)
    Got that, 53 and 54. The second bit was a joke really. Had to try and explain how CF is 1 longer then CEF which makes same journey without E the shortest route. Was not spending ages on that figuring out a totally different part!

    Alot of it was just time wasting. You had to find 2 alternating paths for one question. No need for that, it didnt test any knowledge finding the second one, just took up time that no one had to spare!

    Also, the last questions on the simplex thing didnt make much sense. Didnt know what to put to prove that it was not optimal
    It was not optiman because the non-basic variables were not all 0 and there were negative basic variables.
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    (Original post by Womble548)

    Also, the last questions on the simplex thing didnt make much sense. Didnt know what to put to prove that it was not optimal
    isnt it cos theres a negative value in the profit row?
 
 
 
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