Delta decided to invest $200,000 lump sum into a marketable security, earning 10% annually. Delta decided to use the money to buy nearby commercial land in the 21st year, and currently, the land is valued at $800,000, appreciating at 4% per year.

After a quick calculation, the company found that it is still short of securing the land with the saved money. So the company decided to create a saving account by depositing equally for the next 21 years to have enough money to buy the commercial land.

How much must the company save every year for the next 21 years to make up the lump sum that is still short of buying the land? (Assuming the interest rate is 10% also)

Include methods for HP10bII+ calculator as well.