Miranda wants to retire after 40 years and get retirement income of 100 000 dollars per year for the next 20 retirement years. She also wants to leave 500 000 dollars for her son after she dies which is 20 years after her retirement.

Miranda can save 12 000 dollars per year for the next 20 years and all savings earn 6% annual interest. How much Miranda has to invest on the 21st years to be able succeed in her plan?

Use excel functions to calculate.