Students struggle in the first question on this activity. They have to figure out how they can answer the questions given in context and how that can help them sketch what the graph of the profit curve looks like. There are often a lot of great discussions that happen around this question. I find that once they are done with this question they find the rest of the activity easier but I really need to check that they are doing what each question asks. For instance that when they are asked to justify with the first derivative they are doing that. It is a good idea to have a discussion at the end of the activity and pull together all of the different approaches that we now have to understanding how a function is behaving. An important point to make at some point in this activity is that very little of these ideas are new - they have worked with all of them before. We are now just asking them to pull them together.