How would you calculate the IRR? (Please include all calculations)

Thanks.

Scenario analysis is the determination of what happens to NPV estimates when we ask what-if questions We can consider a number of possible scenarios, but let's start with worst case and best case For our project, these values would be the following: Worst Case Best Case Unit sales 5,500 6,500 Price per unit 75 $ 85 Variable costs per unit $ 62 58 Fixed costs per year $55,000 $45,000