Linear Programming Question 113

Question: Minimize $ z=\sum\limits _{j=1}^{n}{{}}\sum\limits _{i=1}^{m}{c _{ij}x _{ij}} $ Subject to : $ \sum\limits _{j=1}^{n}{x _{ij}\le a _{i},\ i=1,…….,m} $ $ \sum\limits _{i=1}^{m}{x _{ij}=b _{j},\ j=1,……,n} $ is a (L.P.P.) with number of constraints

[MP PET 1999]

Options:

A) $ m+n $

B) $ m-n $

C) mn

D) $ \frac{m}{n} $

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Answer:

Correct Answer: A

Solution:

Condition (i),

$ i=1,x _{11}+x _{12}+x _{13}+…..+x _{1n} $

$ i=2,x _{21}+x _{22}+x _{23}+……+x _{2n} $

$ i=3,x _{31}+x _{32}+x _{33}+……+x _{3n} $ ………………..

$ i=m,x _{m1}+x _{m2}+x _{m3}+…..x _{mn}\to $ constraints

Condition (ii),
$ j=1,x _{11}+x _{21}+x _{31}+……+x _{m1} $

$ j=2,x _{12}+x _{22}+x _{32}+……+x _{m1} $ ………………..

$ j=n,x _{1n}+x _{2n}+x _{3n}+……+x _{mn}\to n $
constraints
Total constraints = $ m+n $ .