You are Here: Home >< A-levels

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

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. (Original post by Nikhilm)
I'm pretty sure you could've done it in 4 bins not 5?

Posted from TSR Mobile
I ended up with 4 bins
2. (Original post by FugFig)
Nah i am pretty sure now its 65. 75 was the second smallest pair, and for the 65 the path was tricky, so i think the others just didnt see it.(at least i hope so)
Yeah the path for 75 was ridiculous, pretty sure I ****ed up that whole question
3. Also, if I got the objective function wrong (which is obviously -1 mark), are there ecf marks for the next question?
4. (Original post by ediosaurus)
In some papers you get penalised 1 mark
My teacher told me that u won't but idk tbh
5. I've just read a past mark scheme and it says 'condone lack of numbers', just as long as you don't put activities in the nodes...
6. How many marks were questions 2, 7 and 8?
7. (Original post by Dannyfire)
How many marks were questions 2, 7 and 8?
5 11 and 14
8. (Original post by TrueDAN)
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

For Algorithm one, some people say because 1/2 for X will give a never ending result as u'd keep halving the X value ( giving: -/2 -/4 -/8 -/16 ....)

I agree with it even though I didn't get in the exam
9. (Original post by lucabrasi98)
They do lol. It says so on the front page

Only an idiot draws diagrams in pen anyway
Umm... I guess I was one ( with the amount of TIME we had to swap pens)
10. last question: 9x and 5y giving maximum capacity given the budget of 520 as it cost a total of 505
11. What do you think the grade boundaries will be like? I totally screwed up this paper and I need an A overall, I guess I'm just going to have to ace C3 and C4 lol
12. For part 2 of the flowchart was the reason not because a fraction can be neither odd or even?
last question: 9x and 5y giving maximum capacity given the budget of 520 as it cost a total of 505

that doesn't fit the constraint of 7x+8y<112
14. Prims was 69 or 70?
15. (Original post by brokeins1)
For Algorithm one, some people say because 1/2 for X will give a never ending result as u'd keep halving the X value ( giving: -/2 -/4 -/8 -/16 ....)

I agree with it even though I didn't get in the exam
Oh yes I suppose - grrr another 2 marks I may have dropped. But wasn't the input of the algorithm:
Is X odd
If yes, X = X-1
So inputting 1/2 would take you to that procedure which encounters negatives? Cannot remember it well enough
16. (Original post by s0phi33)
What do you think the grade boundaries will be like? I totally screwed up this paper and I need an A overall, I guess I'm just going to have to ace C3 and C4 lol
I wanted high 60s in that test and have came out with high 40s Certainly lower than normal, do not think a lot of people will have got over 60 in it due to the time constraints. I do not want to speculate, but I could not see an A being over 60 at all. Maybe even 55, who knows - just smash C3 and C4 and do not worry about D1 It was not a test of how good you are at maths at all - really disappointing exam.
17. Doesnt anyone have a copy of the paper?!!!!!
18. (Original post by TrueDAN)
Oh yes I suppose - grrr another 2 marks I may have dropped. But wasn't the input of the algorithm:
Is X odd
If yes, X = X-1
So inputting 1/2 would take you to that procedure which encounters negatives? Cannot remember it well enough
I guess you have to realate it to the diffenition of an algorithm being finite, and so wouldn't be in thiscase where you have 1/2 =x. OR with this value u'd get a wrong output ( a negative answer, whereas xy= +61

Btw was it not 1 mark?????
19. So no one had a copy of the paper then?

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: June 21, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll

## All the essentials

### Student life: what to expect

What it's really like going to uni

### Essay expert

Learn to write like a pro with our ultimate essay guide.

### Create a study plan

Get your head around what you need to do and when with the study planner tool.

### Resources by subject

Everything from mind maps to class notes.

### Study tips from A* students

Students who got top grades in their A-levels share their secrets