
Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion 
 LinkBack  Thread Tools  Display Modes 
July 18th, 2016, 04:00 AM  #1 
Newbie Joined: Jul 2016 From: tehran Posts: 2 Thanks: 0  how to selecte 2 inequalities between three inequalities for solving linear programmi
hi i saw a question in a book for liner programming in solving the question i faced three inequalities as follow 1 3x+2y<= 5000 2 1x+.5y<= 1600 3 4x+5y<= 9600 in book they select 1 and 3 inequalities for solving simultaneous equation, i cant understand the logic for this. anyone know the logic? thanks in advances 
July 18th, 2016, 10:42 AM  #2 
Math Team Joined: Jan 2015 From: Alabama Posts: 3,261 Thanks: 895 
Didn't you graph these? That should be the first thing you do with problems like this! First, those are "dashes" after the "1", "2", and "3" right? I first mistook them for minus signs! To graph "3x+ 2y<= 5000", Graph the line "3x+ 2y= 5000" and, since, x= 0, y= 0 lies "to the left and below" that line, that is the set of points "to the left and below" that line. Similarly for the other inequalities. Graphing (as I did in about three minutes), you should see that the two lines given by "x+ .5y= 1600" Also, did you read the entire solution to the problem? They can't get the answer by finding only the intersection of the lines 1 and 3. They would also need to find the intersection of lines 2 and 3. The intersection of lines 1 and 2 are above the line 3 so not relevant. 
July 18th, 2016, 09:10 PM  #3 
Newbie Joined: Jul 2016 From: tehran Posts: 2 Thanks: 0 
thanks dear country boy as i understood, because this is a profit maximizing problem and so the optimal point is on intersection of line that is more far from the origin this mean " the intersection of line 1 and 3" and for finding the exact amount, equation 1 and 3 must be selected. the intersection of line 2 with other line is not a optimal point so must forgive this one. thank you very much again. 

Tags 
inequalities, linear, programmi, selecte, solving 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
I need help with solving inequalities.  itchygo  Algebra  4  January 17th, 2015 06:30 AM 
Solving system of linear equation and inequalities  App  Algebra  1  January 7th, 2014 07:29 PM 
Solving system of linear equation and inequalities  App  Algebra  2  January 6th, 2014 12:54 AM 
Solving Two Inequalities  fishsticks1907  Algebra  4  February 7th, 2012 04:39 PM 
solving inequalities  michellekorte  Algebra  6  October 22nd, 2011 08:10 PM 