Half Life Problem with Animal Population

Question

The current population of a threatened animal species is 1.7million, but it is declining with a​ half-life of 25 years. How many animals will be left in 40 years? in 55 years?

Answer 1

The decay law is

p(t) = 1,700,000 (1/2)^t/25

where t is in years and p(t) is the population at time t. Plug in 40 and 55 for t.