Question

A certain forest covers an area of 4500 km^2. Suppose that each year this area decreases by 8.75%. What will the area be after 5 years?

Answer 1

The area of forest after 5 years is 2846.93 square kilometer

Solution:

Given that, A certain forest covers an area of 4500 square kilometer

Suppose that each year this area decreases by 8.75%

To find: Area after 5 years

The decrease function is given as:

$y = A(1-r)^t$

Where,

y is the value after t years

A = initial amount

r = decreasing rate in decimal

t is the number of years

Here in this sum,

A = 4500

t = 5 years

$r = 8.75 \% = \frac{8.75}{100} = 0.0875$

Substituting the values in formula,

$\begin{aligned}&y=4500(1-0.0875)^{5}\\\\&y=4500(0.9125)^{5}\\\\&y=4500 \times 0.632651\\\\&y=2846.93\end{aligned}$

Thus the area of forest after 5 years is 2846.93 square kilometer