What will the area be after 11 years

Question

a certain forest covers an area of 1800km^2. Suppose that each year the forest decreases by 5.75%. What will the area be after 11 years?

 

round your answer to the nearest square kilometer 

Answer 1

At the end of each year, the area is (1 - 0.0575) times what it was at the start of the year.  That is 0.9425 times as much.  Keep this up for n years and you end up with

 

A(n) = 1800 (0.9425)ⁿ km²

 

A(11) = 1800 (0.9425)¹¹ = 938.4 km²