Consider the case of the following annuities, and the need to compute either their expected rate of return or duration. Raul needed money for some unexpected expenses, so he borrowed exist4, 267.94 from a friend and agreed to repay the loan in eight equal installments of exist800 at the end of each year. The agreement is offering an implied interest rate of Raul's friend, Sadler, has hired a financial planner for advice on retirement. Considering Sadler's current expenses and expected future lifestyle changes, the financial planner has stated that once Sadler crosses a threshold of exist37, 620, 367 in savings, he will have enough money for retirement. Sadler has nothing saved for his retirement yet, so he plans to start depositing exist85,000 in a retirement fund at a fixed rate of 10.00% at the end of each year. It will take years for Sadler to reach his retirement goal