Answer:
about 19 years
Step-by-step explanation:
The formula for determining the total amount at the end of an investment, with interest compounded annually is,
![P * (1+r)^(n) = F](https://img.qammunity.org/2021/formulas/business/high-school/q28kvjrogavs9i8g5aaj2k5fmiv5xb0i7o.png)
where P is the amount invested,
r is the rate of return
n is the number of years
and F is the total amount at the end of the investment.
Therefore, for $1 invested today to triple ($3) at 6% annual rate,
![1 * (1+0.06)^(n) = 3](https://img.qammunity.org/2021/formulas/business/high-school/cb9g5ztnew3f894gb53jbl880aftc490bi.png)
=
![(1+0.06)^(n) = 3](https://img.qammunity.org/2021/formulas/business/high-school/zg9kwbjb2jigllnf1qm3l7nqu8cjq841f8.png)
By interpolation, the value of n that satisfies the equation is 18.9.
Therefore, the investment will triple in 18.9 years.