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

1. (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

arsey on linear programming i drew the x + y < 90 right and the y= x+30 right but the other constraint wrong therefore labelling the region wrong can i get 2 marks? i also therefore got d wrong can i get follow through marks for d? i also drew the objective line? can i get 1 mark in d for that?

Also in route inspection; i said the right arc and right finish point i said BD instead of BE,CD does it matter?
2. (Original post by Arsey)

FFS! I even wrote out which letters I needed to do.

Hands up who spent 5 min looking for O

Damn you Edexcel and your stupidly big Gantt chart.
Throws the old saying "One mark a minute" out the window doesn't it.
3. i am not sure if this is right but i said the number of small(2 seaters) must be at at most two thirds of big(4 seaters) is this right someone please?
4. (Original post by Arsey)
no point worrying about it now. Save your energy for smashing the other modules. Win the war, accept loses in battles.
for the cascade diagram, if you had drawn all the activities in, but get the floats wrong for some, or even get the actual activity times wrong, how many marks can you get up to providing the gantt chart is exactly the same as my original activity network?
5. Goodbye any hope of a decent university

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6. Guys would I get penalised on the matchings for not drawing improved and final matching?
7. (Original post by Arsey)
no point worrying about it now. Save your energy for smashing the other modules. Win the war, accept loses in battles.
I love you man.
8. Does anyone know how many marks I'll lose for plotting everything right for the LP question, but marking the region R incorrectly.

Obviously, I then used vertex testing on the wrong points.. I don't even know if D1 has a such thing as error carried forward.

Also, I'm almost certain I got a U in this exam (due to circumstances and me not feeling well). Do you think universities will see this as a one off freaks result considering I have 5 A's in my other modules?

I could really kill myself right now..

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9. (Original post by lebron_23)
Does anyone know how many marks I'll lose for plotting everything right for the LP question, but marking the region R incorrectly.

Obviously, I then used vertex testing on the wrong points.. I don't even know if D1 has a such thing as error carried forward.

Also, I'm almost certain I got a U in this exam (due to circumstances and me not feeling well). Do you think universities will see this as a one off freaks result considering I have 5 A's in my other modules?

I could really kill myself right now..

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Well I think D1 isn't that kind compared to Core modules with follow through marks. You'll lose that one mark and a few more. But relax like arsey said whats done is done, what can't go back so do best in other modules. Besides I doubt you got a U, considering the linear programming was difficult compared to rest.

And if you got A's in all other modules and have C in this, you have a higher end B. assuming that these A's are 80 and not >80.
10. sorry guys.i have a question to ask.
is it the test paper in uk is different to the test paper in other countries?
i had a completely different paper on that day.
11. (Original post by moko)
i am not sure if this is right but i said the number of small(2 seaters) must be at at most two thirds of big(4 seaters) is this right someone please?
Yes
I did a couple of statements (which I believe will score 2 marks)

Here they are:

http://youtu.be/xip-Z4JwGOM

Arsey I am happy to remove the link if you dont want it on the thread
12. (Original post by 041087)
sorry guys.i have a question to ask.
is it the test paper in uk is different to the test paper in other countries?
i had a completely different paper on that day.
It has been for the other units so I believe it will be for D1.
13. Looks like that might be full marks if for the CPA they accept day 22 with a similar reason to the one given on the model answers (got 5 as the lower bound), good luck everyone

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14. Guys I have a question about the Venn Diagram. Instead of writting out the actual numbers in it, I wrote out the probabilities. In essence, it's correct but will I get the marks or even some of the marks? Thanks

15. the 2x<3y question i said there must be at most 1.5 times as many 2seaters than 4 seaters is this right?
16. For 3E I got 12 as it doesn't specify only having one builder, could this be right? But apart from that I reckon I didn't drop any other marks, thanks
17. For the cascade chart, I represented the floats using dotted lines because I didn't know you were supposed to shade it in. Would I lose any marks?
Also, for the part after the cascade chart, I actually scheduled the workers, assigning certain activities to workers and got 5 workers. Would this be worth 2 marks?
18. I dropped a mark by somehow misinterpreting the objective function as 100x + 400y- will I lose the 1 mark or more? & will I lose marks for not labelling the region R by forgetting? -.-
19. (Original post by Kakashidude101)
For the cascade chart, I represented the floats using dotted lines because I didn't know you were supposed to shade it in. Would I lose any marks?
Also, for the part after the cascade chart, I actually scheduled the workers, assigning certain activities to workers and got 5 workers. Would this be worth 2 marks?
(1) I doubt it as dotted lines are usually the accepted method (unless Edexcel want to be picky)

(2) That would be ok but a lot of work for 2 marks.
20. In the bin question
Do u have say how many wasted ??

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