D1 OCR MEI - Discussion

gman2k8

Oh and can someone tell me how they criticised the Network for that girl and her sweets or something.

In the model you could (and did, in the algorithm) go backwards up a main course. Obviously you couldn't do that in the real world, so the intended solution was to add arrows to make it a digraph.

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I messed up the second part of the CPA because I forgot you needed to reduce B and A, not just A. My linear programming is a mess but I got the right answer assuming they can interpret my scribbles. £45200 is what I got. I didn't manage to figure out why you could rephrase the LP in part ii) though.

What did you put for 1. iii) where it was "why do two people have the same number of handshakes"?

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Do you think it was an easy or hard paper compared to normal? It will affect the UMS and I think I'm on the A/B boundary.

Reply 21

Thamizhan

OP

gman2k8

I dunno were I went wrong, I might have messed up the constraints but then again they gave us those didnt they? oh well the question was 9 marks weren't it?

Yes, it was 9 marks.
For the handshake question, part 3, I wasn't sure as to how to explain that atleast two people shake hands the same number of times?!
Stimulation question - 96-99 (reject/redraw), correct? Fraction (probablity) was 3/5 (or 0.6)?

Reply 22

jayshah31

14

Thamizhan

Yes, it was 9 marks.
For the handshake question, part 3, I wasn't sure as to how to explain that atleast two people shake hands the same number of times?!
Stimulation question - 96-99 (reject/redraw), correct? Fraction (probablity) was 3/5 (or 0.6)?

I got 96-99 to reject, and 3/5 as the probability :biggrin:

Reply 23

gman2k8

Simulation thats what I got aswell thank god 96-99 ignore, and for CPA if you reduce both A and B and you get 300 right? and for the handshake one I left if blank, and as for grades I don;t know I'm hoping for atleast a B cause paper was just average imo.

Reply 24

tanka

jayshah31

Nope..

I got £4400 because it was a "maximise to" question - (8,4) is £4400 maximised. How did everything convert the minimise problem to a maximum one for 3 marks?

I'm not sure
2000x1 + 2200x2 + 2500x3 =< minimise
x1+x2+x3=20
x3=20-x2-x1
2500x3=50000-2500x2-2500x1
2000x1 + 2200x2 + 50000 - 2500x2 - 2500x1 =< minimise
-500x1 - 300x2 =< -50000
500x1 + 300x2 >= maximise

Reply 25

Thamizhan

OP

Game_boy

In the model you could (and did, in the algorithm) go backwards up a main course. Obviously you couldn't do that in the real world, so the intended solution was to add arrows to make it a digraph.

--

I messed up the second part of the CPA because I forgot you needed to reduce B and A, not just A. My linear programming is a mess but I got the right answer assuming they can interpret my scribbles. £45200 is what I got. I didn't manage to figure out why you could rephrase the LP in part ii) though.

What did you put for 1. iii) where it was "why do two people have the same number of handshakes"?

--

Do you think it was an easy or hard paper compared to normal? It will affect the UMS and I think I'm on the A/B boundary.

In the model, some of the meals were repeated for minimal cost and you wouldn't do that in the real world, or maybe you would. I don't know.

Yes, I reduced both A and B because if you only reduce A then the minimum time would be reduced to 55 mins, so reducing both A & B will help it reduce the time to 50 mins at £250.

Are you sure £45200 is right?

Reply 26

gman2k8

Thamizhan

In the model, some of the meals are repeated for minimal cost and you wouldn't do that in the real world, or maybe you would. I don't know.

Yes, I reduced both A and B because if you only reduce A then the minimum time would be reduced to 55 mins, so reducing both A & B will help it reduce the time to 50 mins at £250.

Are you sure £45200 right?

I swear reducing A was 250 and reducing B was like 50 or something like that.