Answer: 180
Step-by-step explanation:
Given
The population of 45 foxes doubles in 10 year period
Population follows [tex]y=45\cdot 2^x[/tex]
After 20 years i.e. x=2 Population is given by
[tex]y=45\cdot 2^2=45\times 4\\y=180[/tex]
Thus, there will be 180 foxes after 20 years