Linear Programming Problem

ItnStln511

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Eric's Carpentry manufactures two types of bookshelves that are 4 feet tall and 3 feet wide, a basic model and a deluxe model. Each basic bookshelf requires 1.5 hours for assembly and 1 hour for finishing; each deluxe model requires 2.5 hours for assembly and 1 hour for finishing. Two assemblers and one finisher are employed by the company, and each works 40 hours per week. Eric can sell more basic models than deluxe models, so he wants the number of basic models produced to be 50% more than the number of deluxe models produced. If he makes $50 profit on the basic models and $65 profit on the deluxe models, how many should he make to maximize the profit? What is the maximum profit?
 
Well, you ARE going to have to set up some equations. If you cannot do it, you certainly cannot wander through the simplex method for a solution. Will we be graphing?
 
tkhunny said:
Well, you ARE going to have to set up some equations. If you cannot do it, you certainly cannot wander through the simplex method for a solution. Will we be graphing?
I believe so. The equations are what's giving me trouble right now.
 
Welll, pick it apart. I'll walk you through it. Once for free.

"Eric's Carpentry manufactures two types of bookshelves that are 4 feet tall and 3 feet wide, a basic model and a deluxe model"

This appears to be just smoke, unless the size will make a difference in the assembly time. I think all we have here is a classification, basic vs. deluxe.

"Each basic bookshelf requires 1.5 hours for assembly and 1 hour for finishing"

BasicCreation = 1.5 Assembly Hours + 1 Finish Hour

"each deluxe model requires 2.5 hours for assembly and 1 hour for finishing."

DeluxeCreation = 2.5 Assembly Hours + 1 Finish Hour

"Two assemblers and one finisher are employed by the company, and each works 40 hours per week."

Total Assembly Hours = 2*40 = 80
Total Finish Hours = 1*40 = 40

"Eric can sell more basic models than deluxe models, so he wants the number of basic models produced to be 50% more than the number of deluxe models produced."

B = Number of Basic Models Sold
D = Number of Deluxe Models sold

B = 1.5*D

"If he makes $50 profit on the basic models and $65 profit on the deluxe models,"

Profit = 50*B + 65*D

"how many should he make to maximize the profit? What is the maximum profit?"

Whew!!! That's all we can glean from the problem statement. Now we need to think about it.

A little compiling from above:
BasicCreation = 1.5 Assembly Hours + 1 Finish Hour
DeluxeCreation = 2.5 Assembly Hours + 1 Finish Hour
Total Assembly Hours = 2*40 = 80
Total Finish Hours = 1*40 = 40

Aha! Then 1.5*B + 2.5*D <= 80 and 1.0*B + 1.0*D <= 40

That looks like enough equations.

Really, paying attention is the hardest part. You just have to wade through it.
 
tkhunny said:
Welll, pick it apart. I'll walk you through it. Once for free.

"Eric's Carpentry manufactures two types of bookshelves that are 4 feet tall and 3 feet wide, a basic model and a deluxe model"

This appears to be just smoke, unless the size will make a difference in the assembly time. I think all we have here is a classification, basic vs. deluxe.

"Each basic bookshelf requires 1.5 hours for assembly and 1 hour for finishing"

BasicCreation = 1.5 Assembly Hours + 1 Finish Hour

"each deluxe model requires 2.5 hours for assembly and 1 hour for finishing."

DeluxeCreation = 2.5 Assembly Hours + 1 Finish Hour

"Two assemblers and one finisher are employed by the company, and each works 40 hours per week."

Total Assembly Hours = 2*40 = 80
Total Finish Hours = 1*40 = 40

"Eric can sell more basic models than deluxe models, so he wants the number of basic models produced to be 50% more than the number of deluxe models produced."

B = Number of Basic Models Sold
D = Number of Deluxe Models sold

B = 1.5*D

"If he makes $50 profit on the basic models and $65 profit on the deluxe models,"

Profit = 50*B + 65*D

"how many should he make to maximize the profit? What is the maximum profit?"

Whew!!! That's all we can glean from the problem statement. Now we need to think about it.

A little compiling from above:
BasicCreation = 1.5 Assembly Hours + 1 Finish Hour
DeluxeCreation = 2.5 Assembly Hours + 1 Finish Hour
Total Assembly Hours = 2*40 = 80
Total Finish Hours = 1*40 = 40

Aha! Then 1.5*B + 2.5*D <= 80 and 1.0*B + 1.0*D <= 40

That looks like enough equations.

Really, paying attention is the hardest part. You just have to wade through it.

Thanks, tkhunny. It turns out that I wasn't as far off as I thought. Here's what I did:
1.5x + 2.5y (</=) 80
x + y (</=) 40
Basic = x
Deluxe = y

2.5y (</=) -1.5x + 80 --> y (</=) -0.6x + 32
y (</=) -x + 40

I graphed y (</=) -0.6x + 32 and y (</=) -x + 40 with the following restrictions: x (>/=) 0, and y (>/=) 0.
Then I graphed x = 1.5y. The three equations intersected at point (24, 16). 24 = 1.5(16).
 
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