Determine the IRR on the following projects:
a. Initial outlay of $35,000 with an after-tax cash flow at the end of the year of $5,836 for seven years
b. Initial outlay of $350,000 with an after-tax cash flow at the end of the year of $70,000 for seven years
c. Initial outlay of $3,500 with an after-tax cash flow at the end of the year of $1,500 for three years