Calculate the internal rate of return

answer this question with manual format and explain it

 Calculate the internal rate of return on the following projects:

a.   Initial outlay of $60,500 with an after-tax cash flow of $11,897 per year for eight years.

b.   Initial outlay of $647,000 with an after-tax cash flow of $118,000 per year for ten years.

c.    Initial outlay of $25,400 with an after-tax cash flow $11,788 per year for three years.

Answer:

a.   IRR = 11.33%

b.   IRR = 12.74%

c.    IRR = 18571%

I will pay %10 total