D1 OCR - 19th January

think i did get x = 4, just couldn't rememebr because i had C4 lesson straight after exam..

shuttle total swaps was 17 i think, comparisons = 23.
bubble was 17 swaps, 30 comparisons
so shuttle more effficient

I hope they do give method marks, because I think I might have made a mistake.

I didn't read it properly and spent about 5 minutes trying to draw a graph with an x, y and z axis. Then I read it and re-did it! What a stupid error.

I got pretty much the same as you PindropSilence.

I got the numbers wrong, but I still said shuttle had less comparisons and so was more efficient so will I still get a mark?

should do, you might have being right with 15, and i'm wrong with 17..
i spent far too long on the shuttle question and not enough time thinking about question 5.. i got totally different to what everyone has said on graph.. for simplex i got P = 20 at x = 4, y = 0, z= 0
for graph i got P = 16 i think.
i'm relying on Method marks for graph.. but thing is i did all the working on graph paper and it's incredibly scruffy because i rushed it.

I have never had to do 5 algorithms on the same graph before! I think they have run out of ideas to make the problem interesting lol.

I thought the paper was ok, but there was a LOT of reading to be done and the shuttle sort took hours.

In 5, what did people put for the other constraint thingy? I couldn't think of anything so I put that she might run out of ingredients...

Did anyone agree that this paper was quite a bit more challenging than previous years? The simplex & linear programming questions at the end were also quite a bugger - considering there were 18 marks just for that.

What was 2iii (why a graph with orders 1 2 2 3 4 cant be a tree)

Was Krukstal's 100 or something? Djikstra's was ok I think; got 56 as the weight. The route was fairly simple - just A up to B, back down to the centre and finally right to G Cant remember any other graph algorithms.

I found shuttle sort quite tricky. Had 8 paths, with 17 swaps and 23 comparisons as well I think (I remember a difference of 7 swaps between bubble & shuttle sort)

The linear programming was ghastly! I still dont know why it was 6x+4y+5z=< 24 (i think) for the preparation times . The only thing that occured to me was 60 mins (the total time) minus 12 + 12 + 12 (the baking times) = 24. Thus 12x + 8y + 10z =< 24. BUT THEN simplifying it down would give 6x+4y+5z=< 12, not 24.

Was the other constraint that they had to be whole integer values?

And the simplex/graph was haard! Profit was 20 on the simplex. Did anyone get 8/3 and something else like that? My final answer was y=3 x=1 or other way round.

Thanks for reading

oh yeah, elliot so your right.. it was 15 for that part..
i just added the other two.. so were all right for that one (hopefully)

Did anyone agree that this paper was quite a bit more challenging than previous years? The simplex & linear programming questions at the end were also quite a bugger - considering there were 18 marks just for that.

What was 2iii (why a graph with orders 1 2 2 3 4 cant be a tree)

Was Krukstal's 100 or something? Djikstra's was ok I think; got 56 as the weight. The route was fairly simple - just A up to B, back down to the centre and finally right to G Cant remember any other graph algorithms.

I found shuttle sort quite tricky. Had 8 paths, with 17 swaps and 23 comparisons as well I think (I remember a difference of 7 swaps between bubble & shuttle sort)

The linear programming was ghastly! I still dont know why it was 6x+4y+5z=< 24 (i think) for the preparation times . The only thing that occured to me was 60 mins (the total time) minus 12 + 12 + 12 (the baking times) = 24. Thus 12x + 8y + 10z =< 24. BUT THEN simplifying it down would give 6x+4y+5z=< 12, not 24.

Was the other constraint that they had to be whole integer values?

And the simplex/graph was haard! Profit was 20 on the simplex. Did anyone get 8/3 and something else like that? My final answer was y=3 x=1 or other way round.

Thanks for reading

For Mr M I think this was at least part of the Linear Programming question

Plain cookies (x) take 12 mins to prepare, 12 mins to bake
Chocolate cookies =D (y) take 8 mins to prepare, 12 mins to bake
Fruity cookies (z) take 10 mins to prepare, 12 mins to bake

Jane has one hour to bake them I think

x y z >= 0
6x+4y+5z=< 24,
(and was there one other restraint?)

There was a proft of £5 and (maybe £7 I think) on two of them. Cant really remember. Use simplex to work out Profit x & y. (10 marks)

Then z was removed, and she wanted to make at least double the number of chocolate cookies as plain cookies (OR the other way around). A graphical solution had to be used (8 marks)

I think profit on x was £5, y was £4 and z was £3. And it was at least double chocolate as plain.

Constraint

wasn't one x + y + z has got to be less than or greater than something.

Why don't we just wait for Mr M to get a copy for himself? It won't take long to, he could post the marks up by tomorrow really... and there would be no doubt