Hello everyone, I'm Michelle. Today this video we are going to learn how to use Excel solver to solve linear programs that start. So ,later we will introduce the solver add-in and teach you how to install it, and then we will show you two examples for it. Solver is a Microsoft Excel adding programs for solving linear programs than linear programs and integer programs. Solver adjust the weight value of decision variables in your model, which will help you to find an optimal solution with satisfying all the constraints. If your operating system is Windows, you can follow the following instruction. Let's turn to excel. So, in Excel, please go to the file tab Go to the button and click options. You will open Excel options box on the left side bar there's add ins please click it. Down at the bottom of this box it says manage Excel Add ins please go ahead click the go bar In the inbox, please check solver add in and click OK. After these steps, you can see solver in data tab here. Okay, let's go back to our presentation. If your operating system is Mac OS, there's a little bit different than windows, but you can also see Excel eighteens in your tool menu. Please click it and you can see the ed inbox, please check Solver add-in and click. Okay. And then you can also see the data bar. There's a solver on the right hand side of the chart. Let's have some example for it. The first one is producing desks and tables. According to the previous videos, professor has formulated these progress, and we let the number of desks produced in a day and the numbers of tables produced in days as our decision variables. Formulation can be the following share is our objective value, which is the total sales profit revenue. And the 1st constraint is the word limitation. The 2nd one is the labor time limitation. The 3rd one is our machine time limitation. And here are our assigned constraints, which is that the number of tables and desk produced cannot be negative. Okay, after the formulation we can use solver aid into finding an optimal solution that's turned back to excel. Okay here for spreadsheet modeling your four things that you need to be formulated before you use the solver ,the first one is the input variables which is here. We have already typing in the, in the on the top of the spreadsheet. And the second one is decision variables, which we leave a space for these green cells. The third one is objective value. And the last one is the constraint. So, we need to type in the objective value function and the constraint function first before we use the solver. So, our objective value is the total sales revenue. So, it is the number. The number of tape desk and tables were going to produce. Cartels, multiply the profit we will earn for each product. And the first constraint is the wood limitation. So here, we need to fill in, how many wood we are going to need. And here we are. The second constraint is the labor hours constraint share, we are going to fill in the function that. How much times we are going to need, and the last constraint is the machine time constraint. We also need to fill in the function that how much machine time we need Okay. After this, the typing all of the objective value function and all the concern function. Now you can try yourself to change the decision variables. Maybe we can try to produce three hundred book ,desk and three hundred tables. And you can see that all of the concern are satisfied. But it seems we can produce more to increase our sales revenue. So, let's see five hundred. If we try to produce five hundred desks and tables, you can see that the first constraint here is unsatisfied. It is exceed three thousand six hundred. And since this we cannot use five hundred. Let's see four hundred. Okay, if you try four hundred we can see that all of the constraints are satisfied. And it is the objective value is more than three hundred, but is it an optimal solution? No. So ,you can try to change your value by ourselves to find an optimal solution, but it may be time consuming or it's hard to find it. So,you can let solver to help you to find an optimal solution. So, click the data tab on the right hand side, there's a solver, click it and you can open the solver parameters box. The set objective please fill in your objective value. So, here since we are going to maximize our sales revenue so we should choose max here. And we are going to change the changing variable cells is the decision variable cells. So, point and drag these cells. Here at the subject to the constraints box, please aid the constraints so we can click ate to aid that. The resource we need must be lesser or equal to the limitation. Click okay and here is our constraint and also don't forget your assign constraint, which you can choose to check make a constraint variables non negative It will align the solution being on there,since we are going to solve it by linear programming. So here the solving method, please choose simplex LP. After days, please click. Okay. You can see that Excel solver help us find an optimal solution. And you can see the constraint are all satisfied. And the first and the last constraint are binding. Okay. Let's come back to our presentation. So, an optimal solution is we are going to produce this amount of desk and these amount of tables and we can earn nearly $8,000 With all the constraint is satisfied
