D2 6th June 2013

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Reply 120

smith50

Original post by Knoyle quiah

Hello just wondering where these questions are from , the old edexcel d1? solomon?

Hi it's D1 January 2006 - old spec contains some of D2 stuff on simplex and flow give it a go and let me now :wink:

as i still do not understand the markscheme.

Thanks,
Smith

Reply 121

smith50

Original post by mathswiz:)

Draw on the arc EJ with capacity 5, then look for how much spare capacity you can have going along this arc. Remember that everything going into an arc must equal everything coming out of the arc. You want to work out what is the maximum flow you can get through the arc EJ and then the same for the arc FH. :smile:

Posted from TSR Mobile

Hi could you help me on the question that i posted earlier :smile:

Thanks,
Smith

Reply 122

smith50

Original post by Lilmzbest

Aah simplex, it just makes you want to cry :tongue:

tbh i just practiced simplex a lot and i'm fairly confident in it now, i just make sure to double check all my answers as soon as i get to the row operations bit, like most of D2 i find that you are more likely to lose marks from wrong calculation than by not knowing what you're doing :tongue:

I'm just getting lots of practice (doing all the exercises in the book) and trying to keep the algorithms fresh in my head, so the exam should be okay i hope :smile:

Hi could you give my question i posted earlier a go :smile:

Thanks,
Smith

Reply 123

mathswiz:)

Original post by smith50

Hi could you help me on the question that i posted earlier :smile:

Thanks,
Smith

Use your labelled diagram with arrows going both ways, add in the arc DG with 100 capacity and 0 flow and augment the network again. :smile:

Posted from TSR Mobile

Reply 124

Lilmzbest

Original post by smith50

Hi could you give my question i posted earlier a go :smile:

Thanks,
Smith

Which one? post no. please, i'm too lazy to go trawling back through the thread :tongue:

Reply 125

smith50

Original post by Lilmzbest

Which one? post no. please, i'm too lazy to go trawling back through the thread :tongue:

post 231

Smith

Reply 126

smith50

Original post by mathswiz:)

Use your labelled diagram with arrows going both ways, add in the arc DG with 100 capacity and 0 flow and augment the network again. :smile:

Posted from TSR Mobile

Thanks, it'sjust that i don't get how they calculate the value of the final flow my answer doesn't match the MS.Could you explain a bit more or even try it as i am so stuck please :colondollar:

Thanks,
Smith :smile:

(edited 10 years ago)

Reply 127

mathswiz:)

Original post by smith50

Thanks, it'sjust that i don't get how they calculate the value of the final flow my answer doesn't match the MS.Could you explain a bit more or even try it as i am so stuck please :colondollar:

Thanks,
Smith :smile:

Augmenting the route SBDGT increases the flow by 86. Add this to 437 and 236 giving you 759 :smile:

Network flow.pdf719.0KB

Reply 128

smith50

Original post by mathswiz:)

Augmenting the route SBDGT increases the flow by 86. Add this to 437 and 236 giving you 759 :smile:

Thanks so much tsr is not letting me rep you anymore .
I would give you 100 if i could :biggrin:

.Your a legend :tongue:

.If you get stuck on anything post it on here
happy to help
Thanks,
Smith

Reply 129

Hamburglar

Hey guys, I was wondering:

If we are formulating a transportation problem as a linear programming problem, and the problem is unbalanced, how do we treat this?

Do we add a dummy demand with zero costs first, and include that in the linear programming?

Thanks

Reply 130

Lilmzbest

Original post by smith50

post 231

Smith

Considering there's only 130 posts in this thread i think you might be reading the wrong number.... i mean the number at the top right of your post :tongue:

Reply 131

smith50

Original post by Lilmzbest

Considering there's only 130 posts in this thread i think you might be reading the wrong number.... i mean the number at the top right of your post :tongue:

Oh i'm sorry it's post 110 :biggrin:

Smith

Reply 132

smith50

Original post by Hamburglar

I don't think you add a dummy but instead of writting your constaints as equations you write them as inequalities.
Hope that helps, :smile:

Smith

(edited 10 years ago)

Reply 133

Hamburglar

Original post by smith50

I don't think you add a dummy but instead of writting your constaints as equations you write them as inequalities.
Hope that helps, :smile:

Smith

Ah the inequalities thing does make sense, thank you :smile:

Reply 134

knowledgecorruptz

Original post by Hamburglar

Ah the inequalities thing does make sense, thank you :smile:

That's not dealt with in the book, is it?

Reply 135

smith50

Original post by mathswiz:)

Use your labelled diagram with arrows going both ways, add in the arc DG with 100 capacity and 0 flow and augment the network again. :smile:

Posted from TSR Mobile

For game theory when representing it the graphical method i sometimes don't get how to choose the optimal point.Could you help me with this please :smile:

Thanks,
Smith

Reply 136

smith50

Original post by knowledgecorruptz

That's not dealt with in the book, is it?

I don't think so but they expect you to know it :wink:

Smith

Reply 137

Hamburglar

Original post by knowledgecorruptz

That's not dealt with in the book, is it?

Not to my knowledge but I was having a peek at practice paper B which I haven't done yet, and there appears to be a question just like that.

I just wanted to know how you'd deal with it and why :tongue:

Reply 138

knowledgecorruptz

Original post by smith50

I don't think so but they expect you to know it :wink:

Smith

Okay, thanks :smile:

Reply 139

sacheeen

Hi guys,

I'm a bit confused when graphing a game theory problem. The optimal point - which one is it?
I've resorted to finding the intersection of all the lines and find the point which gives the highest value but this isn't correct for some reason. Can anyone shed some light on this matter?