Question

The current population of a threatened animal species is 1.2 million, but it is declining with a half-life of 20 years. How many animals will be left in 25 years? in 55 years?

Answer 1

$Rate:\frac{1,200,000}{20}$
$Unit\ Rate:\frac{60,000}{2} = 30,000$

$25\ Years:750,000$
$55\ Years:1,650,000$