Year 12s: what will be the first way you research your future options? >>

OCR Decision 1 - 24 May 2012

Scroll to see replies

q1: Can't remember xD
2) wasn't this drawing the graphs or something?
3)The teacher wanted to set up classes? Draw the network, find a matching with no two joined in one day.. and the last bit was another student joins, why can't it be done any more.
4)Simplex?
5)Some girl who was shopping. First bit was on the route inspection (ie finding the minimum length that covers all arcs). Then we used nearest neighbour from M. Then it was the minimum length without W I think, then the minimum weight with W.
6) This was the one with the flow chart. We had to input x=0, then x=1, then x=-1 and then comment on why it was rubbish :P

I'm pretty sure that's correct, or near to it

Q1) Draw Planar graph
49 weight, route AEF (I think)
1200 seconds

Question 5) 1420
1270

660 (Nearest neighbour)
400-500 region (cant remember exactly)

(edited 11 years ago)

Reply 41

_hannahrose_

That was an awful papperrrr!! resit in january i think!

Reply 42

nffc-b

Was completely clueless on that class sessions one, anyone get it?

Reply 43

Nathdragon5

Original post by travellingsalesman

hey nathan, :wink:

from barney lol

Ooh dear barney, you absolute troll, get outta here xD how was it?

Reply 44

Lucozad

Original post by Nathdragon5

Ooh yeah, shall I put down my answers so far?

Yeah, go for it.

Reply 45

Nathdragon5

Wait, which question was the linear programming, was that 3?

Reply 46

Alex Newton

Original post by nffc-b

Was completely clueless on that class sessions one, anyone get it?

I cant remember my answer, but I started with C1, then the nodes joined to C1 had to be in the other session. Then the nodes joined to those nodes had to be in teh session with C1....

It worked out in the end i think :s-smilie:

Reply 47

Lucozad

Original post by Nathdragon5

Wait, which question was the linear programming, was that 3?

I dunno, maybe 4, because,

1) Dikstras
2)Graph rubbish
3) Classes
4) turing over the page...... Linear programming
5) Simplex...

i Think its like this.

Reply 48

icy elemental

Question 1 involved joining up places with arcs, then using Dijkstra's algorithm to work out the shortest length from A to F. Shortest length was 49, and went AEF. A to E was 18, E to F was 31.
Last part was 1200 seconds but it asked for it in minutes so 20 minutes.

In question two it was graphs. The first part was 5 vertices, 5 arcs and it had to be Eulerian. Just join each vertex to the one next to it to form a pentagon shape.
Part two was 5 arcs, 5 vertices, and you had to form a semi-Eulerian graph with one order-4 vertex. Connect one vertex to all of the others, and then join two of the order 1 vertices together.
Part three was 5 arcs, 5 vertices, sem-Eulerian, none of which were order 4. Begin to form a pentagon shape leaving off just one side so you have two order 1 vertices and three order 2 vertices. Then connect an arc between one of the order 1 vertices to one of the order 2 vertices.

In question three, the first part just involved connecting all of the subjects that were chosen by the same students, eg if student one wanted to do C1 and D1, connect those two vertices.
Part two was work out a way it can be done in two sessions. Pick a subject (eg C1), look at the vertices it is connected to. The ones it is connected two must be in a different session to it for all the students to be able to go to their desired lessons. Continue this until you have 5 in session 1 and 5 in session 2 (I can't remember which the five were off the top of my head). There may have been ways to do it with 4 and 6 or 3 and 7 per session but I doubt it.
Part three asked why more sessions would be required if someone wanted to do D1 and M1. D1 and M1 should have been in the same session in your previous answer, so the student would be unable to attend both if there were only two sessions.
Question 4, the simplex, without the equation I can't really do. All I remember of it is S was equal to 2, T was 0 and U was 0.
There was a linear programming question, can't remember all of the coordinates but the optimum P was at the point where the coordinates were (4/3, 8/3). The next part asked for the integer values which were (2, 2)
Question 5 I can't remember at all with the girl what my weights were :/
And for the algorithm, if you can remember the algorithm I'll post the answers, I think it was X^3 + AX^2 + BX + C where A was -4, B was 5 and C was 1?

Reply 49

88888

Original post by Alex Newton

Q1) Draw Planar graph
49 weight, route AEF (I think)
1200 seconds

Question 5) 1420
1270

660 (Nearest neighbour)
400-500 region (cant remember exactly)

Are you sure about 660 ( Nearest Nighbour) ?????

Reply 50

Lucozad

Original post by 88888

Are you sure about 660 ( Nearest Nighbour) ?????

Yeah, i dont recall 660, either, i think i put down 600, but I could have done it wrong.

Reply 51

Nathdragon5

Okay, so here's the startings of it:

Q1) Draw the network. Length from A to F maybe? and yeah, again, 49 sounds right :smile:

It is quadratic order. Given that it takes 3 seconds(?) to do 200 places, how long will it take to do 400(?) places. Can't remember what I wrote tbh :P Apparently 1200 seconds, which rings a bell
Q2) Draw an eulerian network with 5 nodes and 5 vertices, which is simple and connected
then draw a semi-eulerian with 5 nodes, 5 vertices, 1 with order 4, simple and connected
draw another semi-eulerian with 5 nodes, 5 vertices, no order 4 and simple and connected.
3)If this is the linear programming: you had to work out the equations of the line, I got y=2x, y=1/3x, y=4-x and y=-1.5x+3.... then you had to find the optimum P, which I got as 12, and then you had to find the optimum p with integer values of x and y, which I got was 7, it was max because it was a vertice...
Teacher question: Draw the graph and i failed on the next bit so....
Simplex gave me something that I don't remember but the slack variables I said was the difference between each equation and the total. slack 1 (s) was 2, the others were 0. I said that the others equalled their total, but that this one equalled 10.
5) The shortest path I got was 1440 or around there. Then nearest neighbour was 660 and then the shortest was.... no idea :P it was definitely less than 660 xD
6) If this is the flow chart, I got -1/5 for part 1, then it does the same again, then for part 3 i got -15/16 but i might be wrong.... the last part I had no idea, I think I put that it takes a long time and that the -1 and +1 values got different answers :L

please improve on that xD