A lightsome cruises wants to build a new cruise ship that has an initial investment of 250 million. It is estimated to provide an annual cash flow over the next 15 years of $34 million per year. The discount rate is 10%.

What is the discounted payback period? Enter your answer rounded to two decimal places.

I did a long calculation and I got 12.43. Please break it down for me because I really want to understand. Thanks.