Question

A certain forest covers an area of 3800 km^2. Suppose that each year this area decreases by 7.25%. What will the area be after 5 years

Answer 1

Answer:

After the fifth year, the area will be 2,608.28 square km.

Step-by-step explanation:

Given,

The area is = 3,800 square km. (or, km^2)

Decreasing rate = 7.25% per year.

After 1st year, the area will be decreased to

= 3,800 - (3,800 x 7.25%)

= 3,800 - 275.5

= 3,524.5 square km.

After 2nd year,

3,524.5 - (3,524.5 x 7.25%) = 3,524.5 - 255.52625 = 3,268.97375 sq. km

After 3rd year,

3,268.97375 - (3,268.97375 x 7.25%) = 3,268.97375 - 237.00 = 3,031.97375 sq. km.

After 4th year,

3,031.97375 - (3,031.97375 x 7.25%) = 3,031.97375 - 219.818 = 2,812.15575 sq. km.

After 5th year,

2,812.15575 - (2,812.15575 x 7.25%) = 2,812.15575 - 203.88 = 2,608.27575 sq. km.

Therefore, after the fifth year, the area will be 2,608.28 square km.

If we do a complex method,

The formula will be,

Total area x (1 - decreasing rate)^ year

= 3,800 x (1 - 0.0725)^5 = 2,608.28 square km.