The amount of a sample remaining after t days is given by the equation p(t)=a(1/2)^t/h where a is the initial amount of the sample and h is half-life, in days, of the substance.

2.5 mg

Step-by-step explanation:

Substitute the givens into the equation. A is the initial amount, 16 mg. H is the halflife, 8 days. T is the time in days that has passed, 16 days. So we get P(t)= 10(1/2)^(16/2). This ends up being 10(1/2)^2. 1/2^2 is 1/4. 10(1/4)=2.5 mg

i did it myself and i got 4.2 (b) hope its right

step-by-step explanation: