Please using formular to answer following questions in detail:

1. FInd the present value of an ordinary 5-year annuity where each cash flow is $100 and the interest rate is 8%.

2. Find the present value of a 5-year annuity where the cash flow are $100 at the end of years 6 through 10. The interest rate is 8%.

3. Find the present value of the following cash flow stream: $100 at the end of year 1 and $100 at the end of years 6 through 10. The interest rate is 8%.