Question

The area of a wetland drops by a sixth every five years.

What percent of its total area disappears after twenty years?

Round your answer to two decimal places.

Answer 1

After 20 years, the wetland will have decreased in area by 20/5 = 4 times.

If the area has decreased by a sixth every 5 years, it will decrease by 4/6 = 2/3 after 20 years.

Therefore, the percent of the total area that disappears after 20 years is 2/3 = 66.67%.

Rounding to two decimal places, the answer is 66.67%.