 Cheryl, you really haven't completed your model yet, and that's essential. If you look at the problem, the problem gives you this information up here. We're given the return on the projects, and that's defined as the net present value, which is profit. It's everything minus all the cost. So that is the goal. If you think about which projects you should have, it should be the mix of projects that gives you a total profit that is the highest. So somewhere in your model, you need to have a cell that gives the sum of the profits of the mix of projects that you choose. And I don't see that cell anywhere here. One of your constraints is that you've got to keep the total additional costs less than the budget for the additional costs. And that you have set up, it's the sum of these here, these values you've got multiplied by that. So that will work that as you put 1s and 0s in there, this total cost changes. So that constraint, you have set up. You do not have the number of personnel you set up. You need to do something similar for the number of personnel, which is limited to 35. And if you add these up, I think the total is 55, so you cannot, you're constrained. You can't do every project just because of personnel. If I look at your solver set up there, you've got I-14, which is your total cost, and you're maximizing costs, which is not what you want. You want to maximize return, and you don't have a cell yet. That's why you're struggling with that. You've got changing cells, B13 to BH10, H13, which is this row there, which is correct. That's your decision variables, okay. Then you've got B12 to H12 is less than I-12. Well, that's not going to work. Each one of these cannot be 12, and it's far better to have a equation here or formula here rather than try to force solver to do a formula for you. So I would replace that by changing this cell and fixing this cell. This doesn't make sense to me. Project two is less than equal to four. Project four less than equal to two. If you look at those videos that I linked on how to set up binary decisions, the fellow there goes over almost identical problems to the two constraints you have here. Almost identical. It's in that video, and you need to watch it, and you'll see how to set up the constraints that at most one or two, but not both, can be chosen. And if you pick two, then four, but four can be picked without two. So again, watch that second video particularly that I linked about binary decisions. I can't show it any better than that fellow, so I hope this helps. Cheryl, I just noticed something else in your setup there. You've got B10 to C10, which is the names of the projects equal to one. Obviously, that can't be at all. I don't see that you've set up any thing to get your decision variables to be binary, and maybe that's your intent there, but those are the names of the projects. You can't set those to be equal to one. That's never going to happen. One of the things you should do, which I keep recommending to people, I'm going to close this, is to name your ranges so you can understand what's going on. And I can help you. Go to the formulas, define name, and you can do it a couple of ways. I'm going to clear that out. Let's go here, and these are your decision variables. And I'm going to call those D-E-C-I-S-I-O-N-B-A-R. So I've named that range, and let's see if it's updated here. Aha. See, now it shows up by changing my variables. My decision variables are there. I'm going to close that again, and I'm going to name that formula, define name, add cost. Go back to data, solver, and I didn't save it yet. Let's see, you don't have that in there, do you? Okay, go back here to solver, and you can see that I added a constraint which you didn't have. Additional cost has got to be less than or equal to the budget. That cell is budget, that cell is additional cost. So take the time to name these important cells. It'll be much, much easier for you to put this model together and for someone to look over your shoulder to help you if you take the time to name the cells and name the ranges. It really pays off. Cheryl, I beg your pardon. I see now that you did start using the name manager. You named these project one through seven. Unfortunately, you zeroed in on their titles, and that is a good start toward using the names, but these cells are not part of the model. They're just a label, a title. One thing you did forget to do, and I'll just show you that again to make sure you're not forgetting that. We need to add a constraint that our decision variables are binary, okay? Decision variables, binary.