Answer: The population after five years = 9967
Step-by-step explanation:
The exponential equation for population decay : [tex]P=A (1-r)^t[/tex], where A = initial population r= rate of decay , t= time
Given: A= 42000, r= 25%= 0.25, t= 5
then
[tex]P=42000(1-0.25)^5\\\\=42000(0.75)^5\\\\=42000(0.2373046875)\\\\\approx9967[/tex]
Hence, The population after five years = 9967