Given:
Annual population of butterflies after t years is
To find:
The growth rate.
Solution:
The general exponential function is
...(i)
where, a is initial value, t is time and r is growth rate.
We have,
It can be written as
...(ii)
On comparing (i) and (ii), we get
Initial value :
Growth rate :
Therefore, the growth rate is 8.5%.