I see the answer in the answer for part B in the text book solutions as being 50% and -50% but I can only get excel to show be 50% as the answer can you explain how to get a second IRR in excel?

Consider a project with the following cash flows: 100 +200 -75 a. How many internal rates of return does this project have? b. Which of the following numbers is the project IRR (i) .50%; (ii)-1296; (iii) +596; (iv) +50%? C. The opportunity cost of capital is 20%. Is this an attractive project? Briefly explain