Question

A certain forest covers an area of 2400 km^2. Suppose that each year this area decreases by 5.75%. What will the area be after 8 years?

Answer 1

We have to use the function A(t)= a(1 +/- r)^t
So A is going to be the answer- the area after 8 years. t is going to be 8, because t is time. a is 2400 because that's the starting value. Finally, we're going to turn 5.75% into it's decimal form of .0575. That's going to be r, and because the area is decreasing, we will subtract r from 1.
Our new function is:
A=2400(1-.0575)^8
Simplify a little bit.
A=2400(.9425)^8
Bring .9425 to to power of 8 and then multiply by 2400 because PEDMAS.
A=1494.38366866
The rounded answer is 1494 kilometers squared.