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# *Rough*DECISION 1 EDEXCEL JUNE 17TH MARKSCHEME w/Explained Answers

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1. Getting on this one as fast as possible. I hated this exam, everyone else found it good - maybe decision maths isn't for me but it'll be nice to see how your answers compare.

Question 1:
- A bipartite graph consists of 2 vertices, X and Y. Vertices can only be joined from X to Y, not joined from the same set I.e. X to X.
- It was the most confusing / long winded route I got it as. You were matching P with B.
P-A = ..... M - B and change state.

Question 2:
- Precedence table was with 3 dummies. I did get a nice looking one but I know I made one mistake. C and D were dependent on A. E and F were dependent on B. A and B were dependent on nothing and came from a node labelled O.
Remember to link the all up at the end to create a nice network.

Question 3:
- Quicksort with 10 numbers. I can remember 11 being shifted to the very end after the first pass. Make sure to label pivots clearly and to say that the source is complete.
- First fit decreasing got you 4 bins.
- Lowerbound was 4, the question was asking if it was optimal. Therefore, it was optimal.

Question 4:
- Ouput 135 implying 7 and 25 were multiplied together.
- 122 because using 1/2 would encounter negatives.
- 122 X 1/2 = 61.

Question 5:
- 48 units in length.
- One with J 49 units in length.
- Missed out Prim's question and only noticed at end so rushed like mad - I got 87.
Question 6: Chinese postman
- Weight 459 but I put 460
- Look at one excluding F which was EH and 35 in length.
- 419 with a route with 21 nodes, starting at F and finishing at B.

Question 7:
- for answers of w,X,y,z (not in order) 4,11,17 and 22?
- Gantt chart - hate you - you had 4 critical values. I got 6.
- 5 workers as lower bound looking at day 12-14
- Scheduling = ran out of time / didn't bother really.

Question 8:
- 20x + 65y less than or equal to 520.
- Remember that X.y larger than equal to 0. Plot the points to get a region R - one of the equations I struggled with and I think it was something like:
-X + 24y larger than or equal to 24. I brought the X over and got 0,0 and 0,1 as my points. I don't think it interfered with the region - I may have got it wrong please tell me.
- Exact values you had to look at the point of intersection between 7x + 8y = 120 and 20x + 65y = 520.
I did simultaneous equations and got fractions - I checked there decimal points and it did look close to where V was. I got V to be the upper, right hand side point.

9 and 4 I got for the crates
People got 9 and 5
I ink the correct is 11 and 4.
I think I've done horribly on this paper, please help me add on to it to create a nice markscheme! I really wanted an A overall, think I may have not done enough in this module. Anywho, I will update ASAP and try my best to respond quickly. Good luck all
2. I'm pretty sure you could've done it in 4 bins not 5?

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3. Also I got 82 miles not 87

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4. (Original post by Nikhilm)
Also I got 82 miles not 87

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Thanks! I rushed it so I knew it was wrong - updating!
5. (Original post by TrueDAN)
Thanks! I rushed it so I knew it was wrong - updating!
I'm not sure if 82's right though!

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6. (Original post by Nikhilm)
I'm pretty sure you could've done it in 4 bins not 5?

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You can do it in 4 bins
7. (Original post by Nikhilm)
I'm pretty sure you could've done it in 4 bins not 5?

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4 of the values were larger than 50 though.
8. (Original post by frances98)
You can do it in 4 bins
Yeah so it was optimal

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9. I got 11 and 4 for the containers :/
10. Also I got 14 not 16
11. (Original post by frances98)
You can do it in 4 bins
On it now!
12. (Original post by Nikhilm)
I'm pretty sure you could've done it in 4 bins not 5?

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Lower bound and bins were four
13. (Original post by frances98)
Also I got 14 not 16
Think that rings a bell - that was just a memory issues of the questions! Thanks
14. Did anyone get 430£ for part f, linear question??
15. I got 11 and 4 for the last q
16. (Original post by stuock)
I got 11 and 4 for the last q
Conflict on this question ATM. I think 4 was definitely correct.
17. also I got 9 and 5 for the last question with an amount of 505
18. Damn... That double Gantt chart took so much time.

Ran out of time on the last question, objective function was so weird
19. What was w for critical path? Was it not 11?😭
20. Anyone remember a 459?

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Updated: June 21, 2016
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