1. First, how much Palantium did Mr. Corridge have ownership of in 1905?
Info: In 1880, Mr. Corridge invested $7,000 into an account earning 4.5% interest annually. Then, in 1890, he invests an additional $2,500 into the same account, only to withdraw all funds after only three years, in 1893.
Palantium cost $0.21 per ounce in 1887 and has grown in price linearly at a rate of 0.72 cents ($0.0072) per ounce per year ever since then
It stands to reason that Mr. Corridge withdrew his money in 1893 to redirect all of his investments into something more profitable – Palantium.”

Question

1.	First, how much Palantium did Mr. Corridge have ownership of in 1905?
Info: In 1880, Mr. Corridge invested $7,000 into an account earning 4.5% interest annually. Then, in 1890, he invests an additional $2,500 into the same account, only to withdraw all funds after only three years, in 1893. 
Palantium cost $0.21 per ounce in 1887 and has grown in price linearly at a rate of 0.72 cents ($0.0072) per ounce per year ever since then
It stands to reason that Mr. Corridge withdrew his money in 1893 to redirect all of his investments into something more profitable – Palantium.”

anonymous · Answer

And: Palantium has a half-life of 170 years, that is, if you start with a certain amount of Palantium, then in 170 years, you will have only half of the amount you started with.