You are a civil engineer designing a bridge. The walkway needs to be made of wooden planks. You are able to use either Sitka spruce planks (which weigh 3 pounds each), basswood planks (which weigh 4 pounds each), or a combination of both. The total weight of the planks must be between 600 and 900 pounds in order to meet safety code. If Sitka spruce planks cost $3.25 each and basswood planks cost $3.75 each, how many of each plank should you use to minimize cost while still meeting building code? 1. What is the thing you are trying to minimize or maximize?
2. What are the two variables?
3. Write your objective function: (the thing you are trying to min/max IN TERMS OF the two variables).
4. Write your CONSTRAINTS (the inequality statements that are going to LIMIT your ability to minimize/maximize the objective function).
5. Find any vertices you don’t know (solve the system) and then TEST the vertices in the OBJECTIVE FUNCTION to see which one minimizes/maximizes its value.