What percentage of a sample remains after 50.0 min if it has a half-life of 20.4 min.?

Question

Quizplus · Accepted Answer

The amount of a sample remaining after a certain period can be calculated using the formula for exponential decay, $N = N_0 \times \left(\frac{1}{2}\right)^{\frac{t}{t_{1/2}}}$, where $N$ is the final amount, $N_0$ is the initial amount, $t$ is the time elapsed, and $t_{1/2}$ is the half-life. For a half-life of 20.4 minutes and a time elapsed of 50.0 minutes, the fraction remaining is $\left(\frac{1}{2}\right)^{\frac{50.0}{20.4}}$. Calculating this gives approximately 18.3% of the sample remaining.

What Percentage of a Sample Remains After 50