Singular Construction is evaluating whether to build a new distribution facility. The proposed investment will cost Singular $4 million to construct and provide cash savings of $500,000 per year over the next 10 years.

1. What rate of return does the investment offer

2.If Singular were to invest another $200,000 in the facility at the end of 5 years, it would extend the life of the project for 4 years, during which time it would continue receiving cash savings of $500,000. What is the internal rate of return for this investment?

Need breakdown of formula nad solution, thank you