Answer:
The account increases at the rate of 6.7% a year.
Step-by-step explanation:
An exponential growth model has the following format:
[tex]A(t) = A(0)e^{rt}[/tex]
In which r is the decimal rate of growth of the model.
In this problem, we have that:
[tex]A(t) = 3500e^{0.067t}[/tex]
0.067 = 6.7%
The account increases at the rate of 6.7% a year.