Determine the IRR on the following projects:
a. An initial outlay of $ 10,000 resulting in a single free cash flow of $ 17,182 after 8 years
b. An initial outlay of $ 10,000 resulting in a single free cash flow of $ 48,077 after 10 years
c. An initial outlay of $ 10,000 resulting in a single free cash flow of $ 114,943 after 20 years
d. An initial outlay of $ 10,000 resulting in a single free cash flow of $ 13,680 after 3 years