Question

Turtoneom has a half-life of 4 years. Suppose a company has 400mg of Turtoneom. How much will be left after 20 years?

Answer 1

If $y(t)$ is the mass (in mg) remaining after $t$ years, then $y(t) = y(0) (0.5)^{t/T} = 400 (0.5)^{t /4}$, where $T$ is the half-life period and $y(0)$ is the amount at t = 0 years (initial).

Then at t = 20:
$y(20) = 400 (0.5)^{20 /4} = \text{12.5 mg}$