# Linear Programming

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#1
Linear Programming:

One of the products of Edwards Lifesciences (EL) is artificial heart valves made from the heart valves of pigs. Different sizes of valves are required. However, the size of a pig’s heart valve cannot be ascertained before the heart is purchased and opened. Therefore, EL has a mismatch problem: shortages of some sizes and excess of others.
A program was established to document the size distribution of valves supplied by each supplier, and purchases were made from those suppliers with the needed sizes. Linear programming was used to determine the set of the suppliers that collectively satisfied EL’s demand. Suppose EL purchases pig valves from three suppliers.
The cost and size mix of the valves purchased from each supplier is given in the table below. Each month EL places one order with each supplier. Suppose next month, 250 large, 300 medium, and 100 small valves are needed.

Formulate an LP model that can be used to minimize the cost of acquiring the needed valves, and use Excel’s Solver to solve it.

Supplier 1: 10 (cost per valve \$), 30 percent large, 50 percent medium, 20percent small.
Supplier 2: 14 cost per valve \$, 10 percent large, 60 percent medium, 30 percent small
Supplier 3: 12 cost per valve, 20 percent large, 55 percent medium, 25 percent small.

Now I understand that the following needs to be solved first but I can't figure out how: 10S1+14S2+12S3
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1 year ago
#2
I've moved this over to the maths study help forum, hopefully one of the study helpers will see it soon and be able to help!

In the meantime, it might help them assist you if you format your post a little so it's not just a single big block of text (this can be hard to read) and attach your working so far
3
#3
(Original post by artful_lounger)
I've moved this over to the maths study help forum, hopefully one of the study helpers will see it soon and be able to help!

In the meantime, it might help them assist you if you format your post a little so it's not just a single big block of text (this can be hard to read) and attach your working so far
I know I'm sorry when I tried formatting it it said there was a problem and it couln't save the changes
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#4
[ QUOTE=Acsel;80922812]If you're going to make an account and ask someone to do your work for you, at least format it so that we don't just see one big chunk of text.

What have you done so far and where are you struggling?[/QUOTE]

Hi! Yes sorry for the format when I tried changing it it wouldn't save the changes ...
I have trouble solving theequation as it has 3 variables: 10S1+14S2+12S3
0
1 year ago
#5
(Original post by carleton1819)
I know I'm sorry when I tried formatting it it said there was a problem and it couln't save the changes
Try and edit the post now - maybe copy the formatted version into a separate word/notepad document so you don't have to keep redoing in case there is another problem!
0
1 year ago
#6
(Original post by carleton1819)
..
So, your original post seems to have got lost, but I can see it in people's quotes.

I can't really see any mathematics in what you've posted, it seems to be an exercise in using Excel. And it seems that a necessary table is missing.

Strictly speaking, I don't think this belongs in F38 either. However, I suspect it's your best bet for getting an answer. But I really don't feel it's "in the spirit" of F38, and I think any help is going to end up very close to "doing your homework for you".
0
1 year ago
#7
(Original post by artful_lounger)
..
Sorry - meant to quote you in the post above - the F38 comments are aimed more at you than the OP.
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1 year ago
#8
(Original post by DFranklin)
Sorry - meant to quote you in the post above - the F38 comments are aimed more at you than the OP.
Yes there are some bugs coming up for this thread right now it seems - they're being looked at.

As far as placement of the thread goes, it was largely from a "best fit" approach, nowhere else seemed more appropriate and (from context anyway, I've done almost no LP/optimization work myself) it seemed some of the issue was the OP not understanding some of the underlying maths. It was originally in "university life" which was definitely not ideal, so maths study help seems the closest fit to getting assistance on a broadly mathematical problem.
1
1 year ago
#9
(Original post by artful_lounger)
Yes there are some bugs coming up for this thread right now it seems - they're being looked at.

As far as placement of the thread goes, it was largely from a "best fit" approach, nowhere else seemed more appropriate and (from context anyway, I've done almost no LP/optimization work myself) it seemed some of the issue was the OP not understanding some of the underlying maths. It was originally in "university life" which was definitely not ideal, so maths study help seems the closest fit to getting assistance on a broadly mathematical problem.
Yeah, not saying it's an easy choice. My personal feeling is that this is going to become either "teach the OP the basics of linear programming from scratch" or "do the OP's homework for them", and so I won't be bothering myself.
0
1 year ago
#10
(Original post by carleton1819)
Now I understand that the following needs to be solved first but I can't figure out how: 10S1+14S2+12S3
This is your objective function, the total cost, which you want to minimise.

"Cost of valve from supplier 1" X "No. of valves from supplier 1" + ....

which comes to

10xS1+....
Last edited by ghostwalker; 1 year ago
0
#11
Oh alright I’ll try that thank you for your help I appreciate it
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