To determine the number of products that need to be sold to achieve maximum profit per product sold, I would need to see the specific graph you are referring to. However, generally, the maximum profit per product is typically found where the profit per product curve reaches its peak on the graph.
If you have access to the equation or data relating to the profit per product sold versus the total number of products sold, you can analyze it mathematically (like finding the derivative and setting it to zero to find maximum points), or visually inspect the graph for the highest point in the profit-per-product metric.
Please provide more details about the graph or specific values, and I'll be glad to assist you further!