Question: Find the continuous interest rate that yields a future value of $18,000 in 20 years for each $9000 investment.
1. A single $9000 deposit.
2. An initial $6000 deposit plus a second $3000 deposit made three years after the first.
3. An initial $3000 deposit plus a second $6000 deposit made three years after the first.
4. An income stream of $300 per year.