The area of a wetland drops by 1/4 every 8 years. What percent of its total area disappears after 40 years?

Question

Percent lost %?

Answer 1

I would use the formula

amount = (.75)^(40/8)
= .75^4
= .3164

so after 40 years we have 31.64% left
so the percent lost is 68.36 .

Answer 2

Hmmm. 40/8 = 4?

Answer 3

40/8=5
.75^5=0.2373
100-23.73=76.27%
thanks :)