Try to find optimal solution but did not work

Hello! Right now i'm in the middle of a research related to inventory modelling and there is one paper that i use as main reference. In this paper, the optimal solution was obtained by using excel solver. In order for me to understans how to use excel solver, i try to find the optimal solution from this paper by using excel solver and if the result i obtained is the same as the result in the paper than the way i use excel solver is already correct. I'm pretty sure there is something wrong with the way i use excel solver but i dont know what i did wrong.

I attached my excel file below.
So basically i write all the numerical example and the mathematical modelling from the paper. I wrote the mathematical formula for each cost first and then the total cost. Cost 1 is for formula 1 like the picture i attach below.
and the paper also attached below.

Can you help me to explain what i'm supposed to do to obtained the optimal solution? And by the way, i'm really sorry if my question and explanation is not clear or confusing since i'm not that good in english.

When I open your file, I see a list of input variables (B2:B23). T is in B24, and n is in D24. There are formulas in B25:B34 that are returning errors.

When I check the Solver model, it says it wants to set C23 to a maximum by changing B24. I notice that C23 is a blank cell. When I try to run the Solver model, I get the expected "Target cell must contain a formula" error message.

I have not taken the time to explore the formulas in B25:C34, so I'm not sure which one, if any, ought to be the "target cell," nor have I tried to debug the errors in those formulas. If this were my project, I would identify the correct target cell. Then I would enter a reasonable value into B24 and make sure the target cell (and the other formulas) are calculating correctly. Maybe try entering a few additional values into B24 and make sure everything calculates correctly for a few different inputs. Then see if Solver can find a solution.

In the .pdf it appears that the equation is used to compute the three-echelon supply chain inventory system.
My first suggestion is to search for "Excel three-echelon supply chain inventory system" to make sure that someone else has not already produced a way to accomplish this.
If that doesn't work then it may help if you could give us at least one manually calculated expected result, say for "Cost 1" in cell B25, and explain how the result was obtained.
Let us know if you have any questions.

[note that this is a duplicate of #4]

icebear. DO NOT duplicate threads. Only one thread per topic is permitted. I have merged the two threads.

It also appears that the sample file in this thread is different from the file in the other thread. In this file, there are two tabs. One looks like the same one in the other thread. The "Sheet1" tab in this file looks more complete. I still see errors in B25:D34 that need to be resolved. The few errors that I've caught look like "implied multiplication" type of errors where, for example, you enter ...B16(1-B17)... without the required multiplication operator.

If I "fix" those kinds of errors, I get a value in D34, then Solver seems to be able to find a maximum. At this point, it looks like you just need to go through your formulas and fix the various syntax errors and carefully evaluate and debug them to make sure they are working correctly. I expect that, once you get the formulas debugged, you will have little difficulty with the Solver model.