Question

a certain forest covers an area of 3100 km^2. suppose that each year this area decreases by 8.25%. what will the area be after 15 years? round to the nearest square kilometer.

Answer 1

A decrease of 8.25% means the reduction factor is 100-8.25=91.75%=0.9175.
The shrinkage over 15 years is 0.9175¹⁵=0.27485 approx, so the size of the forest will be 3100×0.27485=852 sq km approx.