What is the definition of the internal rate of return (IRR) (it is efficient to write down the formula)? What are the given information and what is the unknown variable?

I need help understanding how to solve this

Define the term, the variation of PW?

Every year, there is some form of construction work going on at UF's campus. In January 2018, bids were opened for a new building on campus for UFPD. The bid/construction value of the building was set at $5 Million. Another building of similar structure and purpose is planned with a bid opening in January 2023. What is the expected bid for the new building? It is given that in January 2000, the Florida Construction Cost Index had a value of 5550, while in January 2018, that value was 8000. You can use these price indices to calculate an average inflation in construction costs.