If a 250-mg pill has been consumed so that only 31 mg remains after 24 hours, what is the medication's half-life?
A)8 hours
B)4 hours
C)6 hours
D)3 hours

Question

Quizplus · Accepted Answer

The half-life of a substance is the time it takes for half of it to be eliminated or decay. Starting with 250 mg and ending with 31 mg over 24 hours means the substance has gone through multiple half-lives. To find the half-life, we can use the formula for exponential decay, but a simpler approach is to see how many times we can halve the initial amount until we get to or below the final amount. Halving 250 mg repeatedly: 125 mg (1st half-life), 62.5 mg (2nd half-life), and 31.25 mg (3rd half-life). This process takes three half-lives to get to approximately 31 mg, and since this occurs over 24 hours, each half-life is 24 hours / 3 = 8 hours.

If a 250-Mg Pill Has Been Consumed So That Only