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378                Chapter  Ten:  Linear  Programming

            variables, and replace the ith  constraint  anXi+-  •  -+ai nx n  <  bi
            by the new constraint





                                                                   1
                        2
            for  i  =  1, ,..., m,  together  with  X{ +n  >  0,  i  — ,...,  m.
            The  effect  is totransform  the problem  to an equivalent  linear
            programming    problem  incanonical  form:


                           maximize:   z  = C\X\ + •  •  • +  c nx n

                 subject  to:


                                    •
                                                                  h
                                                          x n+i
                 {     a lxxi  +  • • • •  •  + +  a 2nXn  + +  Xn+2  =  b 2
                                            a lnx n
                                                               =
                       a 2\Xi
                               +
                      Q"ml%l    r  " '  '  T  arnn£n  ~r  X n-\- m
                              Xi  > 0,  i =  1,2,..., n +  m.
                 Combining   this  observation  with  10.1.1,  we obtain:

            Theorem     10.1.2  Every  linear  programmingproblem   is
            equivalent  to one in  canonical  form.



            Exercises   10.1
            1.  A publishing  house  plans to issue three  types  of pamphlets
            Pi)  ?2)  ?3-  Each  pamphlet   has to  be  printed  and  bound.
            The  times  in  hours  required  to  print  and to  bind  one  copy
            of  pamphlet  Pj  are  Ui and  Vi respectively.  The printing  and
            binding  machines  can run   for  maximum  times  s  and t  hours
            per  day  respectively.  The  profit  made  on  one pamphlet  of
            type  Pi  is  pi.  Let  xi,x 2,X3  be  thenumbers  of  pamphlets
            of  the  three  types  to  be  produced  per  day.  Set  up  a  linear
            program   in  xi,x 2,x 3  which  maximizes  the  profitp  per day
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