Answer:
a) 600 foxes
b) 720 foxes
Explanation:
See attached spreadsheet.
The rate of population increase is 20% each year. To find a new year's population, multiply the previous year's population by 0.20 (20%) and add that to the previous year. Year 1 would be (500)*(0.20) = 100 new foxes which are added to the year 0 population of 500, which means there are (500+100) or 600 foxes in year 1.
Year 2: (0.20)*(600) = 120 new foxes
Add 120 to the existing 600 to find 720 foxes in year 2,
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A formula that can be used to predict the fox population for any year, n, would be:
P(n) = 500*(1+0.20)^n
where P(n) is the popluation at year n. The 500 is the population at year 0 (the starting population). (1+0.20) is the growth for each year (120%, which means the original population plus 20%). That is raised to the year of interest, n. [When n=0, (1+0.20)^0 = 1]