 So, what if we were looking at the optimal solution? How many units should we sell and of which units? You see we've got a few different ones, our K100, K95, K85, and K5. So we've got a few of these different types. Well, if that's the case, which one should I be selling and which one am I going to be making the money off of the most and which is going to give me the most net income? To do this, what we want to do is we actually want to set our solver. We start by clicking on Solver. Now, what's our objective? Again, Excel is a computer program. It's not a genius. It doesn't know, you know, what does it mean to be optimal? Well, to us, we're saying that we want a specific cell, in this case our B18, to be one of these things, max, min, or some explicit value. If we set it to max, right now, okay, well, what numbers should it be changing? Right now it's just not going to change. What numbers should change? In our case, the numbers I want to focus in on first are obviously our selling points. So I want to sell B4 to E4. Now, if I go ahead and hit Solve, I run into a bit of an issue. One I'll get to the saying in a second, but you notice a lot of numbers. Well, let's think about what I just asked it to do. If I want you to make the net income so big, so big that it has to be all pound signs because it's too big of a number, what's the best way to do that? Well, I'll just sell so much. I'll just sell a lot. I'll just keep on making a lot of these. I'm clearly going to sell them, right? Well, there's a few things that are wrong with that. One, maybe I can't sell that many. I can only sell a 570. Maybe that's a set limit. Also, notice I got a Parts Available section over here. And that means we have a physical limitation going on. So let's actually kind of double back. I can actually do that by selecting Restore Original Values. And that'll actually take whatever I had, and that'll remove it. So one of the things that we can take note of is now not only am I going to see those same things. Notice I still have my changing values, but I can actually add in constraints here. I can actually specify types of constraints that I want. Maybe for example, B13 should stay 570. Again, I just want to go ahead and say that now, let me maximize these numbers, I'm only going to have 570 of them. Now if I hit Solve, what we should see happen is Excel took that idea that the constraint of B13 has to be 570. And I want my net income to be as big as physically possible. Well if we kind of look at this and figure out what was going on here, you see my sales per price per model is 1,018.24. Then over here on K5, this K5 model is $3,200. Well, since it clearly is the most expensive unit, let me just go ahead and only make that unit. All right, I mean that's exactly what happened. He knows, oh well, just make only that unit, all the other ones got zeroed out. Maybe we want to go ahead and we want to continue with that. We want to add in a little bit more. Let's revert back and let's go back to our solver. Now not only do I want to go ahead and take that, one thing I do want to clean up on it, just because I saw it, when I hit solve, notice how suddenly I'm getting a lot of decimal places here. Well as you can guess, I'm not going to make a 0,0,0,0,0,58 portion of a bike. I don't even, what kind of fraction is that, I don't even know. So one of the things I'm going to do is I'm going to also specify that these numbers right here also have to be an integer. Notice I can select this drop down menu and I have that, I actually have the ability to state this is going to be an integer. The next thing I'm going to do is I'm going to specify, maybe I have some limitations. I want to have a bare minimum on all of these. Again the factor I'm working out of, each one of them, there is a set limitation. I need to maintain that's how much the cost is going to be. I need to be producing at least 515 of these bikes this year. So now all of a sudden, if we take a look at that, I've got, these are all going to be at least 515 and when I hit solve, the same thing actually happens. All right, well, since these all have to be 515, I'll just continue to pump this one up. These have to be a minimum of that, this will just stay the big one. We also get to see kind of what my maximum would be. Problem is, if you take a look over here in my parts available, again, I'm running out of a lot of these things really quickly. I'm draining all of my parts available as necessary or as needed and since I'm pumping up my K5 supply, well, carbon fiber frame, I'm out. So we can't actually just arbitrarily go right to that just yet. One of the things we can do, however, is we can actually specify these remaining. Notice we have a few of these parts available. I want to make sure that every one of these stays above zero, zero or above that. That way, I'm now saying, well, make as many as you can, however, don't go into forbidden zone of negative numbers. I can't physically handle a negative carbon fiber. So the last one I'll do is I'll go in here and I'll say to add that these guys right here must remain at least greater than zero, greater than or equal to zero because suddenly now that I have these four parameters, it has to be an integer. We have to sell 570 of them. We have to take a minimum of each on there. We have to maintain at least a greater than zero on our parts. As soon as I hit solve, suddenly what I get is an actual diversified change. Suddenly, oh, well, if that is the case, obviously K5 still continue to make that our flagship item because that's going to give us the most bang for our buck. But then maybe we change things. Maybe we sell a lot of the K95s, the lesser model, only because that's where we have enough parts left and so we can't go with full K5 but we can do a K95. Some of the things we can do is we can also save this. We can actually take this and save this report and I'll just go ahead and name this optimal mix and when I hit OK, that's exactly what it does. Just let me save that for a little future reference.