The ABC manufacturing company has an investment opportunity to produce electric energy storage batteries. As its initial investment, the company would have to spend $4.6 million now to get started, but the government will pay ABC now, a subsidy of $6.8 million. After 3 years, end of year 3, the company would have to make a further investment of $8.8 million to have the manufacturing line ready for production. Starting year 4, the operational costs are expected to be $400,000 per year, and revenues are expected to be $1 million in year 4, and to increase at amount of $200,000 each year thereafter. ABC will need to replace some equipment at year 12, at a cost of $7.8 million. Equipment salvage values at year 20 are zero. Assuming MARR=12%, calculate the IRR of the project in Excel and make sure that there is just one IRR. If not, then calculate the approximate external rate of return