Question

The number of butterflies in an exhibit is decreasing at an exponential rate of decay. The number of butterflies is decreasing by 5% every year. There are 500 butterflies in the exhibit right now. How many butterflies will be in the exhibit in 7 years? Round your answer to a whole number.

Answer 1

349 butterflies

Explanation:

The formula for Exponential Decay =

y = a(1 - r)^t

Where y = Size of population after time t = ?

a = Initial size of population = 500

r = Decay rate = 5%

t = Time = 7 years

Hence,

y = 500(1 - 0.05)⁷

y = 500(0.95)⁷

y = 349.16864805 butterflies.

Approximately = 349 butterflies