Attempts: Keep the Highest:12 8. Implied interest rate and period Consider the case of the following annuities, and the need to compute either their expected rate of return or duration. David needed money for some unexpected expenses, so he borrowed $2,591.78 from a friend and agreed to repay the loan in four equal installments of $800 at the end of each year. The agreement is offering an implied interest rate of David's friend, Keanu, has hired a financial planner for advice on retirement. Considering Keanu's current expenses and expected future Ifestyle changes, the financial planner has stated that once Keanu crosses a threshold of $3,488,301 in savings, he will have enough money for retirement. Keanu has nothing saved for his retirement yet, so he plans to start depositing S70,000 in a retirement fund at a fixed rate of 9.00% at the end of each year. It will take years for Keanu to reach his retirement goal. 2 3 8 9