(Solving for i) (Related to Checkpoint 5.6 on page 176) Kirk Van Houten, who has been married for 23 years, would like to buy his wife an expensive diamond ring with a platinum setting on their 30-year wedding anniversary. Assume that the cost of the ring will be $12,000 in seven years. Kirk currently has $4,510 to invest. What annual rate of return must Kirk earn on his investment to accumulate enough money to pay for the ring?