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# ocr mei d1 - how did everyone find it? watch

1. Hey,
just done the decision 1 paper. i could of done with some extras time. i found it a little bit hard.

what did everyone get on the question where it asked you to give the town where you could use all the arcs to get to cC?
2. I thought it was pretty easy.

For the question where the bridge was added, the answer was you start from Q, cross the bridge to P and then use all the roads from P to C like it previously said you could (if that makes sense).
3. The exam was pretty much straight forward, and I thought 90 mins is enough time... But I was badly wrong.

I was relax, through the first few questions, and missed of question 3 (critical path analysis) because I couldn't draw the network correctly! Thats because the node at the end, I couldn't work out if E was the last node, or did I have to add dummies??

Anyway, I was lucky, that I skimmed through question 5 (simulation, I missed the very last part of this question)
And was able to complete and get a right answer for question 6.
I was going so fast on question 6, there was 50 seconds left and I was doing simultaneous equations simultaneously!

Anyway, alls well ends well.

Btw : what are the grade boundaries...
4. Wow, well in hte old syllabus it the network was really easy, it only needed 4nodes, i normally write so much in hte paper cos in my p4, s2 and p3 exams ive had to have 2-3 extra sheets, but in this one i had none, although the first 2 n a half questions were on the insert, i only used 6pages in total,
And it had the algorithm that i didnt revise too much, but at least it was quite a nice exam all in all. Wow, a whole 15mark question on LP and using hte graphs, i was loving it
Well no point wondering what the grade boundaries are you might aswell wait until the 18th isnt it?
I only had 80minutes, damn 2000 syllabus
5. (Original post by geekypoo)
Wow, well in hte old syllabus it the network was really easy, it only needed 4nodes, i normally write so much in hte paper cos in my p4, s2 and p3 exams ive had to have 2-3 extra sheets, but in this one i had none, although the first 2 n a half questions were on the insert, i only used 6pages in total,
And it had the algorithm that i didnt revise too much, but at least it was quite a nice exam all in all. Wow, a whole 15mark question on LP and using hte graphs, i was loving it
Well no point wondering what the grade boundaries are you might aswell wait until the 18th isnt it?
I only had 80minutes, damn 2000 syllabus
lol, 6 pages Whats there to write about in math, apart from raw working with numbers

Last time I started writing in sentences in the C2 math exam, I felt like I was writing a thesis!

The exam wasn't bad at all, just needed more time.
Btw. mine was a retake.
Last year when I did the exam, it was awful (E) there was a question requiring to use an algorithm to find the highest common denominator (Euclid's), and I got it wrong because I ended up with a non-integer number.

In this exam, there were no questions where we had to apply an algorithm, instead there was this very very easy question about a maze, and how following the left or right wall can allow someone to end up at the other end (exit)
I loved that question
6. Well 6pages cos i have relatively large writing, and i wrote quite abit as my tutors keep telling me off for not writing enough in D&D and Stats exams.
heh 5lines for a 1mark question,
7. (Original post by geekypoo)
Well 6pages cos i have relatively large writing, and i wrote quite abit as my tutors keep telling me off for not writing enough in D&D and Stats exams.
heh 5lines for a 1mark question,
I feel sorry for the pen and papers that you use (jk)
8. (Original post by katykt77)
Hey,
just done the decision 1 paper. i could of done with some extras time. i found it a little bit hard.

what did everyone get on the question where it asked you to give the town where you could use all the arcs to get to cC?

I thought it went pretty well actually Timing was just right I think - I finished with 5 minutes left to check.

It was definitely better than the practice paper I attempted yesterday!
9. The LP question was a bugger and I didn't do very well on that,
but the simulation was excellent, I loved the different tables etc for different nos. of laptops in. How many customers must be made disappointed, question setter with a sense of humour.
Nice maze Q
10. I didn't like the maze question.

Just to check, the solution to the LP was on one of the axes wasn't it- Produce as much G as possible and no F (or vice versa, can't remember which)?
11. oooh i really liked the maze question, it was brilliant!!

i got the answer on the axis, i got 0 litres of F and it was something like 11500 litres of G

What did you get for the new profit if the amount of nutrient mix was increased to 30000 (it was something like that anyways)?
12. (Original post by majikthise)
I didn't like the maze question.

Just to check, the solution to the LP was on one of the axes wasn't it- Produce as much G as possible and no F (or vice versa, can't remember which)?
Thankyou so much for posting that! I got that too, and everyone else I spoke to said that they got "a" amount of G and "b" amount of F.

Overall I thought it was OK, except the maze question which I totally messed up on, oh well!

Oh, and when the amount of nutrient mix was 30000 and not 25000, you could make 15000 litres of 'g', with each litre giving a profit of 20p = £3000 profit.
13. (Original post by katykt77)
i got the answer on the axis, i got 0 litres of F and it was something like 11500 litres of G

What did you get for the new profit if the amount of nutrient mix was increased to 30000 (it was something like that anyways)?
The question was asking for how many F and G should be produced under the constraints of litres and nutrient mix to maximise profit.

Hence you should have started of with something like:

Let x be the number of F manufactured
Let y be the number of G manufactured.
...
maximise 9x + 3y
subject to the constraints ...

something like that
14. (Original post by Vijay1)
The question was asking for how many F and G should be produced under the constraints of litres and nutrient mix to maximise profit.

Hence you should have started of with something like:

Let x be the number of F manufactured
Let y be the number of G manufactured.
...
maximise 9x + 3y
subject to the constraints ...

something like that
With '9' and '3' representing the profit obtained from each litre of 'f' and 'g', yes?
15. (Original post by Aired)
With '9' and '3' representing the profit obtained from each litre of 'f' and 'g', yes?
No sorry typed it out wrong:

maximise 9x + 20y

I think, where 9 represents the cost of F (9p) and 20 represents cost of G (20p)

I got something like 235 of x and 275 of y, (can't remember)

but I certainly didn't get 0 amount of x or y.

And anyway, a company has to make a certain amount of F and certain amount of G. I think some of you found another vertex on the graph in the feasible region.

If you can remember, which equations (constraints) did you use to find the points x and y? (via. simultaneous equations)

I'm pretty sure, I wasn't wrong.
16. (Original post by Vijay1)
No sorry typed it out wrong:

maximise 9x + 20y

I think, where 9 represents the cost of F (9p) and 20 represents cost of G (20p)

I got something like 235 of x and 275 of y, (can't remember)

but I certainly didn't get 0 amount of x or y.

And anyway, a company has to make a certain amount of F and certain amount of G. I think some of you found another vertex on the graph in the feasible region.

If you can remember, which equations (constraints) did you use to find the points x and y? (via. simultaneous equations)

I'm pretty sure, I wasn't wrong.
9 and 20 were the profit, not the cost. It makes sense to get 0 for the amount of 'f' produced, as the profit was only 9p compared to the 20p profit for 'g'.

I think I used something like this;

Maximise 9f + 20g subject to;

f + 2g (less than or equal to) 25000

and... 0.5f + 0.75g (less than or equal to) 12000.

P.S: If you solved the two inequalities simultaneously, you would get an answer with a certain amount of 'f' and 'g', I don't think this is the right answer though. If you drew the profit line on the graph, and then ran it horizontally, the optimum point was on the x axis (or y, depending on which way around you labelled your axis)

Oh, and for the question asking about which town you could set off from and travel along every arc reaching C, I used ideas about the graph being semi-eularian (That being all of the nodes had an even degree, apart from Q and C), meaning that you can only travel along every arc once and only once if you set off from Q or C.
17. (Original post by Aired)
9 and 20 were the profit, not the cost. It makes sense to get 0 for the amount of 'f' produced, as the profit was only 9p compared to the 20p profit for 'g'.

I think I used something like this;

Maximise 9f + 20g subject to;

f + 2g (less than or equal to) 25000

and... 0.5f + 0.75g (less than or equal to) 12000.

P.S: If you solved the two inequalities simultaneously, you would get an answer with a certain amount of 'f' and 'g', I don't think this is the right answer though. If you drew the profit line on the graph, and then ran it horizontally, the optimum point was on the x axis (or y, depending on which way around you labelled your axis)
Yes that looks like something what I did, and then I did solve them simultaneously, to get value for f and g, then I calculated P.

The thing is, I think you wouldn't actually draw the profit line, I can't seem to find any examples in my D1 text book where the actual profit line is considered and drawn, only the constraints are drawn, which would make sense.
18. (Original post by Aired)
Thankyou so much for posting that! I got that too, and everyone else I spoke to said that they got "a" amount of G and "b" amount of F.

Overall I thought it was OK, except the maze question which I totally messed up on, oh well!

Oh, and when the amount of nutrient mix was 30000 and not 25000, you could make 15000 litres of 'g', with each litre giving a profit of 20p = £3000 profit.

thats the profit i got too!!! what did u put as the minunum number of arcs you needed to connect the nodes in the first question? its just me and friends have different answers
19. (Original post by Vijay1)
Yes that looks like something what I did, and then I did solve them simultaneously, to get value for f and g, then I calculated P.

The thing is, I think you wouldn't actually draw the profit line, I can't seem to find any examples in my D1 text book where the actual profit line is considered and drawn, only the constraints are drawn, which would make sense.
I see what you mean, but the question asked you to solve the problem graphically. You should have drawn in the contraints, shaded out the inappropriate regions, and then drew in the profit line. You then slide the profit line until it reaches the very last point inside the feasible region, which is the optimum point (and therefore your solution).

If you solved it using simultaneous equations, you would have ended up wit the answer giving the largest amount of product (I think), rather than the proportion of f:g produced that gives the highest profit.
20. (Original post by katykt77)
thats the profit i got too!!! what did u put as the minunum number of arcs you needed to connect the nodes in the first question? its just me and friends have different answers
You were supposed to give the sum of the node orders weren't you? I got 12, and then 14 when the junction box was introduced.

P.S: Sorry, I've just realised I've made a double post...

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