Edexcel D1 - 17th June, 2016 [Exam discussion]

For the objective function I wrote C=10x+15y without simplifying further, would that affect the number of marks I'd achieve


Posted from TSR Mobile

It did say to write 'an objective function', it didn't ask about simplest form or anything. It's correct so you should get full marks (if the rest of the question is correct). If they were strict about that then you would only lose 1 anyway but I doubt it

Hey all - so after going over my markscheme and what answers everyone got, I think ive got just below 50 marks - 48ish. Quite disheartened atm, feel really bad - I think C1 ive got 71/75 and C2 around 60/75 so I wanted a solid test to secure the A. I also do further maths and did bad on Fp1 50/75, started panicking because I ran out of time and did not even realise - Im really strong at Fp1 too which sucks, but M1 I think I have got around 64/75 so pulled it up a bit. I have got D2 left to learn - if I can really do well in that, is there still a chance of an A? Because then 4 of my modules will have 60 marks plus and two of them will be around 50? Then surely if I resit FP1 next year it will all be good.

It's not worth thinking about past exams to be honest. I'm in A2 now, and, like you, I tried to predict my grade last year. Turns out I was way off. I predicted As in most of my modules and, instead, got Bs in most of them. Forget that these exams have ever happened

Don't worry about it until results day.

Put all of your efforts into D2. I reckon dynamic programming will be difficult this year considering last years was a godsend.

For the algorithm question which of 122 and 0.5 should be X, I said 122 because it is an integer value, would this gain any of the marks? @Student403 @NotNotBatman

It's really hard to tell with D1, but that should get you the mark as x had to be an integer to get a value of 0.

Awesome. Cheers

What was your opinion on the paper?

Standard paper, but somehow I forgot things during the exam. I couldn't even draw the activity network, so I did an extremely messy one with about 4 overlaps. There were no questions that were very different from questions in previous papers, so I'm guessing 61 for an A. I haven't checked answers with anyone else yet, so I don't know how many I got wrong, but I will have the question paper next week, so I can check.

Standard paper, but somehow I forgot things during the exam. I couldn't even draw the activity network, so I did an extremely messy one with about 4 overlaps. There were no questions that were very different from questions in previous papers, so I'm guessing 61 for an A. I haven't checked answers with anyone else yet, so I don't know how many I got wrong, but I will have the question paper next week, so I can check.

I'd argue the questions were fairly standard but it was just a really time consuming paper, 61 for an A seems too low no?

I'd argue the questions were fairly standard but it was just a really time consuming paper, 61 for an A seems too low no?

I managed to get that activity network but I had to do two curved lines to get the final arcs to the final node. Oh well...


Also, for the one about why starting at an odd node I put:

Starting at an odd node means that there will only need to be one repeated pair of nodes, therefore the overall weight will be reduced by starting at an odd node

Or something very similar - is this acceptable?

I'm thinking some people would have struggled with the linear programming, making the boundaries a bit lower than usual. In recent years the boundaries have been a bit lower too.



You need to explain that the graph is semi-traversable, so you'd probably lose a mark there.

I'm thinking some people would have struggled with the linear programming, making the boundaries a bit lower than usual. In recent years the boundaries have been a bit lower too.



You need to explain that the graph is semi-traversable, so you'd probably lose a mark there.

For the very last question I found V as an exact value, then did point testing with integer solutions around it, subbing them back into the inequalities to see if they satisfy. In the end I got 11,4 or something. Then the last part asked for the COST. This really tripped me up and I was about to cross everything out but I then decided to sub 11 and 4 into the cost inequality that you found out in part a) or something, did anyone else get the same?

Also, for the 24y - x => 24 did anyone else get the line going through 0,1, and 24,2? that was the only way to get it on with a gradient of 1/24, please let me know if you put the same.

For question 7 the scheduling with an extra 6 leniency, did anyone else manage to do it using 3 workers?

what if you write, it makes the graph semi eulerian which means you can start at one odd node and end at another odd node.