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

For the flow chart, was it 135 as the ouput, something like 80+55?

Does anyone know the breakdown for the linear programme question?

output t = 135

algorithm multiplies x + y together

What multiplies what to what?

What multiplies what to what?

The algorithm's output was simply the product of x and y, so yes the output was 135

What was the value of x and y?

Overall, it was x and y: as 27 X 5 = 135.

(The trace-table had you doing 80 + 55 - so, that was definitely right!)

You then had to use this multiplication in part (b)(ii): 122 X (1/2) = 61.

x = 27, y = 5

(a) 2 marks (for the cost inequality)
(b) 4 marks (for the graph)
(c) 1 mark (for the objective function)
(d) 3 marks (for the objective line and optimal vertex's location)
(e) 2 marks (for finding the exact co-ordinates of V)
(f) 3 marks (for finding integer solutions and the corresponding cost)

Total: 14 marks.

I hope that this helps!

(By the way, I don't even know how I managed to remember that!)

The algorithm's output was simply the product of x and y, so yes the output was 135

Do you know how many marks that was worth?

Does anyone know the breakdown for the linear programme question? Or just the marks breakdown in general. Would be helpful for everyone

I think the first part might have been 5 and then the second part 3

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Can remember get 135 from 80+55 = 135, but cant remember doing 27*5. I'm screwed

I was something like this (I'm pretty sure, at least!):


Matchings:
(a) 2 marks (definition of a bipartite graph);
(b) 3 marks (alternating path).
{Total: 5 marks}

Activity network:
5 marks (drawing only).
{Total: 5 marks}

List of numbers:
(a) 4 marks (quick sort);
(b) 3 marks (bin-packing);
(c) 2 marks ("Is this solution optimal?".
{Total: 9 marks}

Flow Chart:
(a) 4 marks (trace-table);
(b) 3 marks - (i): choice and explanation (presumably 2 marks);
(ii): new output (presumably 1 mark);
{Total: 7 marks}

Shortest route:
(a) 6 marks (Dijkstra's algorithm);
(b) 2 marks (A to F, via J);
(c) 3 marks (Prim's algorithm);
(d) 1 mark (weight of MST).
{Total: 12 marks}

Route inspection:
(a) 5 marks (repetition and length);
(b) 2 marks (explanation: starting at a vertex with an odd degree);
(c) 2 marks (determining the finish point);
(d) 2 marks (route and new length).
{Total: 11 marks}

Critical path analysis:
(a) 3 marks (finding the values of w, x, y and z);
(b) 4 marks (cascade/Gantt chart);
(c) 2 marks (lower bound);
(d) 3 marks ([that really annoying] schedule!).
{Total: 12 marks}

Linear programming:
(a) 1-2 marks [I'm not quite sure...] (finding a cost inequality);
(b) 3-4 marks [the same thing again!] (plotting [and shading] the graph);
(c) 1 mark (stating the objective function);
(d) 3 marks (drawing an objective line, and locating the optimal vertex);
(e) 2 marks (calculating the exact co-ordinates of V);
(f) 3 marks (seeking for integer values, and then calculating the corresponding cost).
{Total: 14 marks}*

(*I know that that comes to 15 marks, but I can't quite remember exactly where I seemed to just add an extra one in... Was it only 1 mark for the cost inequality? 3 for the graph? It was something like that...)

{Grand total for paper: 75 marks} [Obviously!]


Wow - that took a pretty while to do! After all, that was all from memory! I sincerely hope that this can help!

I was something like this (I'm pretty sure, at least!):


Matchings:
(a) 2 marks (definition of a bipartite graph);
(b) 3 marks (alternating path).
{Total: 5 marks}

Activity network:
5 marks (drawing only).
{Total: 5 marks}

List of numbers:
(a) 4 marks (quick sort);
(b) 3 marks (bin-packing);
(c) 2 marks ("Is this solution optimal?".
{Total: 9 marks}

Flow Chart:
(a) 4 marks (trace-table);
(b) 3 marks - (i): choice and explanation (presumably 2 marks);
(ii): new output (presumably 1 mark);
{Total: 7 marks}

Shortest route:
(a) 6 marks (Dijkstra's algorithm);
(b) 2 marks (A to F, via J);
(c) 3 marks (Prim's algorithm);
(d) 1 mark (weight of MST).
{Total: 12 marks}

Route inspection:
(a) 5 marks (repetition and length);
(b) 2 marks (explanation: starting at a vertex with an odd degree);
(c) 2 marks (determining the finish point);
(d) 2 marks (route and new length).
{Total: 11 marks}

Critical path analysis:
(a) 3 marks (finding the values of w, x, y and z);
(b) 4 marks (cascade/Gantt chart);
(c) 2 marks (lower bound);
(d) 3 marks ([that really annoying] schedule!).
{Total: 12 marks}

Linear programming:
(a) 1-2 marks [I'm not quite sure...] (finding a cost inequality);
(b) 3-4 marks [the same thing again!] (plotting [and shading] the graph);
(c) 1 mark (stating the objective function);
(d) 3 marks (drawing an objective line, and locating the optimal vertex);
(e) 2 marks (calculating the exact co-ordinates of V);
(f) 3 marks (seeking for integer values, and then calculating the corresponding cost).
{Total: 14 marks}*

(*I know that that comes to 15 marks, but I can't quite remember exactly where I seemed to just add an extra one in... Was it only 1 mark for the cost inequality? 3 for the graph? It was something like that...)

{Grand total for paper: 75 marks} [Obviously!]


Wow - that took a pretty while to do! After all, that was all from memory! I sincerely hope that this can help!

Don't worry - you never did have to do 27 X 5; this was only what the algorithm achieved, overall. This and that addition both gave 135. This is how I knew to then do 122 X (1/2) in part (b)(ii), in order to give 61.

So at the end 80+55 = 135 would get you the full marks provided u didnt make any mistakes?