How many of each type of air compressor should the company produce to maximize profit?

Solve Problem and Applications:  ch 13- prob 7 [Klein Industries manufactures three types of portable  air compressors] in page 451 at the end of chapter 13 in your textbook,  USA 5th edition. The data is given as part of the question. There is no  external data set provided. Use what is given by the problem.
 

13-7.  Klein Industries manufactures three types of portable air compressors: small, medium, and large, which have unit profits of $20.50, $34.00, and $42.00, respectively. The projected monthly sales are: 
 

                         Small  Medium  Large 

 Minimum  14,000   6,200     2,600 

 Maximum  21,000  12,500  4,200 
 

 The  production process consists of three primary activities: bending and  forming, welding, and painting. The amount of time in minutes needed to  process each product in each department is shown below: 
                                            Small  Medium  Large   Available Time  
Bending/forming      0.4          0.7           0.8         23,400 
  Welding                       0.6         1.0            1.2         23,400 
  Painting                       1.4          2.6           3.1         46,800 
   
How many of each type of air compressor should the company produce to maximize profit? 
   a.   Formulate and solve a linear optimization model using the auxiliary  variable cells method and write a short memo to the production manager  explaining the sensitivity information. 
   b.   Solve the model without the auxiliary variables and explain the  relationship between the reduced costs and the shadow prices found in  part a.