Excel solver ???

[Rubiquil]

Hi everyone,

First of all I'm dutch so I'm sorry if my English isn't completely correct. But I've got some problems with the solver of excel.
At our math course we just started to use the solver so it's all new for me.

We received some nice cases from our teacher to solve...and I got the same problem with each case.
For example we need to minimize the total buying cost of some new machines.

The constraints and objective are given and clear to me. We also received the nice excel sheet with everything allready filled in, including the right formulas (I checked them of course). So if I then try to 'solve' it says 'solver has found a solution' but everything in my sheet stays the same, so I did something wrong I guess...

I hope this is clear and somebody can please tell me what I'm doing wrong....because I can't finish my homework right now....

Thank youray:

Rubiquil


I already tried to use the help function and I've also looked up the problem on the microsoft website. But there's no information about this problem.
The help function says step by step how to fill in the solver and I did it correctly (I guess) but there still is no result.
I also searched on this board but I didn't found any topic concerning the same solver problem.

 

[c_m]

Rubiquil,
Welcome to the Board.

One reason for the variable to not change its value eventhough running a solver could be: if the variable has a value that makes the equation's outcome equal to the target value, the value of the variable wont change (or in other words...the problem already came solved).

Also, if you are dealing with polynomial functions, lets say 3rd order, it will have three roots. Therefore, if the variable has a value equal to one of the roots of polynomial function, using solver doesnt change any values.

Try doing this:
Change the variable value by yourself and then use solver.
Here is an example:
Lets say B1 is the variable
Cell B2 has the equation =B1^2-B1-6
and B3 is the target value of the equation.
The equation in B2 is a quadratic equation with two roots -2 and 3. If B1 has a value -2 or 3, using a solver will not change its value because the outcome of the equation and target value are same. Try changing it to -1 or 2 or something to arrive at the answer.

 

[Rubiquil]

Thanks for your reply.

The variables in my case are 10, 15 and 5. In our manual we received, the solved sheet is also given and the optimal solution gives the variables 8, 21.333 an 0. So the variables should change when I'm solving it!

Thank you for your ideas, the might be helpful another time.

This morning I surfed to www.solver.com an they have like tutorials to use solver. I (again) followed every step and filled in my solver but still the same result, nothing changes...