Question

A certain forest covers an area of

3400 km^2. Suppose that each year this area decreases by 7%. What will the area be after 15 years?

Answer 1

Okay. I'll use a formula that my math teacher taught me.

3400(1-0.07)^15
3400(0.93)^15
3400(0.33670086205)
1144.78293098 ( which rounds to about 1145 square km )

Answer 2

1144.78 Km^2

Explanation:

If the forest covers an area of 3400 km^2 and it decreased by 7%, the new area covered after a year will be equal to 3400 less the product of 3400 and 7%

= 3400 - 7% * 3400

= 3400 (1 - 0.07)

After the second year, the area becomes

= 3400 (1 - 0.07) - 7% * 3400 (1 - 0.07)

= 3400 (1 - 0.07)(1 - 0.07)

= 3400 (1 - 0.07)²

Following this pattern, the area after 15 years

= 3400 (1 - 0.07)^15

= 1144.782931 km^2