Question

At the beginning of an environmental study, a forest covered an area of 1500 km². Since then, this area has decreased by 5.8% each year.

Lett be the number of years since the start of the study. Let y be the area that the forest covers in km?.
Write an exponential function showing the relationship between y and t.

Answer 1

Area covered by the forest in the beginning = 1500km²

Decrease in area each year = 5.8% = 5.8/100 × 1500 = 87km²

Decrease in the area of the forest in t years = 87t

Area of forest now = y

y = 1500 - 87t