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Mei ocr d1 2016

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Reply 20
that paper ****ed me up so bad. RIP MEI, even with low grade boundaries.
Reply 21
Original post by JordanL_
Ugh I wish I'd done that, I kept checking the precedence table to see if it was wrong and then trying to redraw the network. You probably got it right, I dont think it was possible to do it without crossing arcs.

Yeah I thought Q3 was alright, Id seen something similar in a past paper. For the octahedron? The complement graph had 2 separate sets of 4 vertices joined up, so you needed one colour for each set.


Yeah I got the same for the octahedron
Missed soo mnay questions, ran out of time so bad :frown: literally did the last question, the one on networks in the last five minutes.. ended up doing kruskal for both even tho one said prims:/
I am completely finished, that exam ruined me. I've been getting 95% or above on every mock I've done and today I'll have been lucky to scrape a C. There are actual tear stains on my exam paper, I have never cried in an exam. That was dreadful. I needed to get an A in this so I could fail c3 and c4 but pass overall, now it's logistically impossible for me to pass maths a level.

When I saw random numbers on the first question I was gutted, I'm good at that and I knew it meant there would be the other topics as long questions. Why only choose 3 numbers? Question 2 on graphs is pretty much the only graph question I've ever understood. Question 3 was ok can't really remember it. Question 4 I had absolutely no idea, what were you meant to define X and y as since you already had X and y in other things? I rearranged for z but can't have done it right because the graph was completely wrong, so there's 16 marks out the window. Question 5 was CPA and scheduling? The network was a bit weird because of how many start activities and dummies but I think it was right. The scheduling I got myself in a tizz about though, I had it so that you had to stop halfway through an activity in room 3 when you reached the 6 weeks, then wait for activity in room 2 to finish then continue it after. So that was wrong. Question 6 was prim and kruskal etc, think that went ok but couldn't make a good answer to if you did 2 lots of dijkstra whether that would be easier or not.

Overall I reckon 48 ish at absolute most for an A. I've done a paper with 51 as an A and that was still quite easy, I'm praying for ridiculously lower grade boundaries meaning I get a C.
Original post by BlackDove
Why only choose 3 numbers?.


Because the maximum number of simulations per employment of the strategy is 3 i.e., lose £100, lose £200 then lose £400. Since the guy only had £1000 to begin with, this would therefore be the stopping point.
Reply 25
Original post by BlackDove
I am completely finished, that exam ruined me. I've been getting 95% or above on every mock I've done and today I'll have been lucky to scrape a C. There are actual tear stains on my exam paper, I have never cried in an exam. That was dreadful. I needed to get an A in this so I could fail c3 and c4 but pass overall, now it's logistically impossible for me to pass maths a level.

When I saw random numbers on the first question I was gutted, I'm good at that and I knew it meant there would be the other topics as long questions. Why only choose 3 numbers? Question 2 on graphs is pretty much the only graph question I've ever understood. Question 3 was ok can't really remember it. Question 4 I had absolutely no idea, what were you meant to define X and y as since you already had X and y in other things? I rearranged for z but can't have done it right because the graph was completely wrong, so there's 16 marks out the window. Question 5 was CPA and scheduling? The network was a bit weird because of how many start activities and dummies but I think it was right. The scheduling I got myself in a tizz about though, I had it so that you had to stop halfway through an activity in room 3 when you reached the 6 weeks, then wait for activity in room 2 to finish then continue it after. So that was wrong. Question 6 was prim and kruskal etc, think that went ok but couldn't make a good answer to if you did 2 lots of dijkstra whether that would be easier or not.

Overall I reckon 48 ish at absolute most for an A. I've done a paper with 51 as an A and that was still quite easy, I'm praying for ridiculously lower grade boundaries meaning I get a C.


I feel your pain completely, this sounds exactly like the exam went for me, the worst exam I've ever taken in my life :frown: I left the first question till the end and forgot to go back to it because I was stressing out about the LP one which I couldn't figure out how to do anyway :frown: please please let the grade boundaries be low...
Original post by MintyMilk
Because the maximum number of simulations per employment of the strategy is 3 i.e., lose £100, lose £200 then lose £400. Since the guy only had £1000 to begin with, this would therefore be the stopping point.


Dammnit, I used £1000 as he put in £1000, not that that was his total. Balls, another couple of marks down the drain.
For the first question I had no idea, I ended up with him winning an average of £40 after the 5 simulations. The linear programming was ok but it took me a while to understand the scenario, not sure if I got it right but I ended up with x=10, y=0 and z=10 for the minimum wasteage.

For the one with the octohedron, I ended up without separate sets for the compliment graph which I assume was wrong but I just ended up making up an explanation for why this means you only need two colours, something to do with the order of the vertices all being even :lol:

That question about the play took me agessss, I just thought the way they presented the information was way too clumsy and more time was needed for the amount of marks you get for each part, i was about to finish the schedule table thing when my time ran out :frown:

Not sure if I got all the marks on the mountain village question, especially the part when it asks if there would be less computation if you did each side separately...

I can't remember the other question?
Original post by MintyMilk
Because the maximum number of simulations per employment of the strategy is 3 i.e., lose £100, lose £200 then lose £400. Since the guy only had £1000 to begin with, this would therefore be the stopping point.


If he won 3 times in a row couldn't he continue though? I couldn't see anything in the question which suggested that after a certain amount of wins, he would stop.
Reply 29
With changing the algorithm for I think Q2 I think I've figured it out but far too late now, I change it to two different algorithms for 30 days and 31 days and now realised there are 365 days in a year ....
Original post by Alex621
If he won 3 times in a row couldn't he continue though? I couldn't see anything in the question which suggested that after a certain amount of wins, he would stop.


He can only win once - he stops playing when he wins. I'm fairly sure that was indicated in the question, although I could be wrong. I probably am, **** sake :bawling:
Original post by JordanL_
He can only win once - he stops playing when he wins. I'm fairly sure that was indicated in the question, although I could be wrong. I probably am, **** sake :bawling:


it probably did say that, it would make much more sense if it did :frown:

I also just realised that during the exam i was convinced that there are 364 days in a year
Original post by Alex621
it probably did say that, it would make much more sense if it did :frown:

I also just realised that during the exam i was convinced that there are 364 days in a year


:rofl: I missed the part of the question where you needed to know that, so it's okay.

Not sure if you've already said, but how did you do on Q5, the activity network?
Original post by JordanL_
:rofl: I missed the part of the question where you needed to know that, so it's okay.

Not sure if you've already said, but how did you do on Q5, the activity network?


Yeah i mentioned it earlier but basically i got really muddled trying to sort out the precedence table but I think i got it right in the end, i didn't get time to finish off the room schedule because i spent ages trying to fit everything in before re-reading the question and seeing that 3 of the activities didn't need a room :angry:
Original post by Alex621
Yeah i mentioned it earlier but basically i got really muddled trying to sort out the precedence table but I think i got it right in the end, i didn't get time to finish off the room schedule because i spent ages trying to fit everything in before re-reading the question and seeing that 3 of the activities didn't need a room :angry:


What did your activity network end up looking like? When I tried to draw mine it had 5 activities coming from the source node and arcs crossing all over the place, so I thought I'd done the precedence table wrong. Spent far too long going back and trying to work out what I'd done wrong, and in the end I just missed out the rest of the question :bawling:
Original post by JordanL_
What did your activity network end up looking like? When I tried to draw mine it had 5 activities coming from the source node and arcs crossing all over the place, so I thought I'd done the precedence table wrong. Spent far too long going back and trying to work out what I'd done wrong, and in the end I just missed out the rest of the question :bawling:


I sketched it out twice on the question paper to try to arrange it in the neatest way before I actually did it in the answer booklet but mine had 5 coming from the source too, and then I think I had dummies going from a and b to c, then one more somewhere else. It was still a mess but I hope it's clear enough. I think I remember getting A and K as critical activities, and then 2 or 3 more.
You absolutely had to cross lines with dummies so don't worry about it, you did it right. I even did a past paper the other day in which you *had* to cross with the dummies, according to the MS, so you're good.
Original post by Alex621
I sketched it out twice on the question paper to try to arrange it in the neatest way before I actually did it in the answer booklet but mine had 5 coming from the source too, and then I think I had dummies going from a and b to c, then one more somewhere else. It was still a mess but I hope it's clear enough. I think I remember getting A and K as critical activities, and then 2 or 3 more.


I sketched it 4 or 5 times before giving up :rofl: I'm not sure about the dummies, I think you'd need A, B and C to have dummies all going to one node, and then you'd need a dummy from C to another for I. They all crossed over so then I tried I think what you described or something vaguely similar. Just so annoying to lose out on all those marks because I couldn't do one part of the question :frown:

Good luck, let's hope for low boundaries!!
Original post by WhiteBison
You absolutely had to cross lines with dummies so don't worry about it, you did it right. I even did a past paper the other day in which you *had* to cross with the dummies, according to the MS, so you're good.


Oh ****. If I'd known you could do that I could have answered the question. I thought you couldn't do it so I didn't answer :bawling: :bawling: :bawling: :bawling: :bawling:ughhhhhhhhhhhhhhhhhhhh
Original post by JordanL_
Oh ****. If I'd known you could do that I could have answered the question. I thought you couldn't do it so I didn't answer :bawling: :bawling: :bawling: :bawling: :bawling:ughhhhhhhhhhhhhhhhhhhh


Don't worry too much about it. It was an abnormal paper, and the removal of the buffer of a Section B simulation question, combined with the 3-dimensional LP (which, fyi, is extension material in the textbook), means that the grade boundaries will be low.

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