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# D1 (Decision 1) 17 May 2013 Official Thread Watch

1. (Original post by sam1837)
Really? The Gantt table took me 5 - 10 mins tops and I had 10 minutes left at the end, shame it's hard to check your answers in D1 as the only real way too do so is to redo the whole question.
what did you get for the total float for activity M
2. Thought it was a great paper, think I've lost 6 or 7 marks which is unexpected for me, been getting high Cs and low Bs on past papers

There were a few little things that threw me though, which meant I had to stop and go over it all in my head which could have been time better spent.The feasible region not being enclosed meant that I spent five minutes trying to figure out where I'd gone wrong

I also didn't like how they left a 17 mark question until last, had to rush it as I had about ten minutes left - my cascade chart was hilarious

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3. Hi guys, just wondering, well clutching at straws here but if you got the wrong feasible region, would you get any marks for trying to calculate the optimal point??
4. (Original post by jiaxinchen1993)
what did you guys get for the total float for activity M?
4

(Original post by Fortitude)
Hi guys, just wondering, well clutching at straws here but if you got the wrong feasible region, would you get any marks for trying to calculate the optimal point??
Ah sorry to hear that ! I actually put R in the one that seemed like the region because I was running out of time, then when testing points I was like oh wait what ?! O_o

You should get some follow through marks / method marks
5. (Original post by posthumus)
4

Ah sorry to hear that ! I actually put R in the one that seemed like the region because I was running out of time, then when testing points I was like oh wait what ?! O_o

You should get some follow through marks / method marks
How are you

No, the total float of M was 8 not 4
6. (Original post by posthumus)
4

Ah sorry to hear that ! I actually put R in the one that seemed like the region because I was running out of time, then when testing points I was like oh wait what ?! O_o

You should get some follow through marks / method marks
Hi, thanks I was really rushing it as I was running out of time
7. (Original post by otrivine)
How are you

No, the total float of M was 8 not 4

(Original post by Fortitude)
Hi, thanks I was really rushing it as I was running out of time
Ah so did I... I left the linear programming one till the end, I couldn't seem to plot the damn points But managed finish the paper within the last minute. Don't worry too much about that particular question now How was the rest of the paper?
8. (Original post by posthumus)
I think otrivine over here is right what did you get ?
& I know... D1 I pretty much rushed the whole paper and still finished just on time
for which question

These were my answers for the last part

a) total float of M=8
b) no effect and second one has effect on completetion as 2 days extra are added
c) lower bound 172/53= 3.something hence 4 workers are needed
d) i drew the gantt chart
e) I said at time 12 activities dont remember but got 4 and one i said may be doing so 5 workers needed
f) i said to use the 4 workers but this is wrong
9. Hi guys,

Question 4:

On Dijkstra's algorithm, I drew the route wrong. I got 31 as my minimum distance, but got part B correct. This means I have at least three boxes on the diagram wrong, but the rest are correct. Any idea how many marks I'll lose?

Question 6

I got A and B correct, but I couldn't draw the line 2x=3y. Don't ask me why, I just couldn't! I drew all other lines on correctly, and got the objective function formula correct. Part E, I interpreted the wrong lines. Will I still receive marks for interpreting a intersection via two simultaneous equations?

How many marks do you guys think I will lose in total?

I hope everyone found the exam okay, as I know for a lot of us it was a good chance of securing an A grade, unfortunately I don't think I got so lucky!
10. (Original post by otrivine)
for which question

These were my answers for the last part

a) total float of M=8
b) no effect and second one has effect on completetion as 2 days extra are added
c) lower bound 172/53= 3.something hence 4 workers are needed
d) i drew the gantt chart
e) I said at time 12 activities dont remember but got 4 and one i said may be doing so 5 workers needed
f) i said to use the 4 workers but this is wrong
I don't think I did part b)
Pretty much the same except for f) I wrote 5 is more reliable/useful as it takes float into consideration. I don't know if that's right though.
11. (Original post by posthumus)
I don't think I did part b)
Pretty much the same except for f) I wrote 5 is more reliable/useful as it takes float into consideration. I don't know if that's right though.
yes answer was 5, that gantt took most of the time i swear!

what you did not do part b? why

how much do u think u got from Arsey mark scheme?
12. (Original post by otrivine)
yes answer was 5, that gantt took most of the time i swear!

what you did not do part b? why

how much do u think u got from Arsey mark scheme?
I did the gantt chart free hand

I think I forgot to do it lol

& I recon above 60... just to play it safe I must focus on the next lot of exams now !
13. (Original post by posthumus)

Ah so did I... I left the linear programming one till the end, I couldn't seem to plot the damn points But managed finish the paper within the last minute. Don't worry too much about that particular question now How was the rest of the paper?
For the total float I can't really remember but 8 sounds very familiar so I think that's what I got. The rest of the paper I think I managed ok, I also left the LP till the end which kinda explains why I messed up though but at least I wrote down the obj function (yes 1 mark!) Because I have a tendency to think that if I don't do one part I probably can't do the rest. Surprisingly I found S1 easier but I know that was totally because I didn't have as much of a timing issue like I did with D1, oh well I'm pretty sure I improved from last time, well I should have.
14. (Original post by posthumus)
I did the gantt chart free hand

I think I forgot to do it lol

& I recon above 60... just to play it safe I must focus on the next lot of exams now !

You know the linear programming I never in all past saw a R region being on the open sided , I was tempted to put the R group below where the lines were closed cause I thought I was doing it wrong! But thank god I didnt! And the bin packing I thought I was doing it wrong as usually in all past papers there is 5 bins and then first fit decreasing u get 4 bins!but this had 4 bins in both, it was trying to test people on confidence very sneaky
15. (Original post by otrivine)
You know the linear programming I never in all past saw a R region being on the open sided , I was tempted to put the R group below where the lines were closed cause I thought I was doing it wrong! But thank god I didnt! And the bin packing I thought I was doing it wrong as usually in all past papers there is 5 bins and then first fit decreasing u get 4 bins!but this had 4 bins in both, it was trying to test people on confidence very sneaky
That's exactly what I did
16. (Original post by Fortitude)
That's exactly what I did
it was a trick! But how did u do in other question
17. (Original post by otrivine)
You know the linear programming I never in all past saw a R region being on the open sided , I was tempted to put the R group below where the lines were closed cause I thought I was doing it wrong! But thank god I didnt! And the bin packing I thought I was doing it wrong as usually in all past papers there is 5 bins and then first fit decreasing u get 4 bins!but this had 4 bins in both, it was trying to test people on confidence very sneaky
I did that without testing regions lol I literally did half LP question within 2 minutes.... I had so much trouble plotting Objective Function as well first i did 100x + 300x = 900 ... too small rubbed it out then same with 100x + 300x = 1800
then finally 100x + 300x = 3600 ... my objective line was still too small though
I agree with the bin packing I can't remember if I got it right though, but definitely got 4 bins for both

(Original post by Fortitude)
For the total float I can't really remember but 8 sounds very familiar so I think that's what I got. The rest of the paper I think I managed ok, I also left the LP till the end which kinda explains why I messed up though but at least I wrote down the obj function (yes 1 mark!) Because I have a tendency to think that if I don't do one part I probably can't do the rest. Surprisingly I found S1 easier but I know that was totally because I didn't have as much of a timing issue like I did with D1, oh well I'm pretty sure I improved from last time, well I should have.
Yup let's not worry too much At least we all know we've improved ! Just hoping for very low grade boundaries now !!!

Any of you guys doing C2 next week ???
18. (Original post by otrivine)
it was a trick! But how did u do in other question
I think i did ok, but the Gantt chart took me ages!!! I hope they're able to read mine because the activities they'd already drawn were very small & so I did my activities very small as well. But yeah I think it was the LP Q which messed it up for me because I was panicking I wouldn't finish & rushed it like crazy
19. (Original post by Fortitude)
I think i did ok, but the Gantt chart took me ages!!! I hope they're able to read mine because the activities they'd already drawn were very small & so I did my activities very small as well. But yeah I think it was the LP Q which messed it up for me because I was panicking I wouldn't finish & rushed it like crazy
For quick sort , I was running out of time did it fast but think I got it correct! as my final answer at the end was correct, but it was a bit messy I hope they wont penalise me for that.
20. (Original post by otrivine)
For quick sort , I was running out of time did it fast but think I got it correct! as my final answer at the end was correct, but it was a bit messy I hope they wont penalise me for that.
I think a lot of people has a prob with timing in that paper esp considering the last 2 Qs were very long & worth a lot of marks so just like posthumus stated I hope Grade boundaries are low because I would say that there were some tricky bits to some of the questions plus what happened to the easier contraints/inequalities we used to get? Like y>3 etc?

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