The answer is the last option
Answer:
Step-by-step explanation:
![$\frac{\sqrt[3]{343^{-3}}}{\sqrt[4]{81} } $](https://tex.z-dn.net/?f=%24%5Cfrac%7B%5Csqrt%5B3%5D%7B343%5E%7B-3%7D%7D%7D%7B%5Csqrt%5B4%5D%7B81%7D%20%7D%20%20%24)
![$\frac{\sqrt[3]{\frac{1}{343^{3}} }}{\sqrt[4]{81} } $](https://tex.z-dn.net/?f=%24%5Cfrac%7B%5Csqrt%5B3%5D%7B%5Cfrac%7B1%7D%7B343%5E%7B3%7D%7D%20%7D%7D%7B%5Csqrt%5B4%5D%7B81%7D%20%7D%20%20%24)
![$\frac{\frac{\sqrt[3]{1} }{\sqrt[3]{343^3} } }{\sqrt[4]{81} } $](https://tex.z-dn.net/?f=%24%5Cfrac%7B%5Cfrac%7B%5Csqrt%5B3%5D%7B1%7D%20%7D%7B%5Csqrt%5B3%5D%7B343%5E3%7D%20%7D%20%7D%7B%5Csqrt%5B4%5D%7B81%7D%20%7D%20%20%24)
Answer:
For cobalt-60, which has a half-life of 5.27 years, 50% remains after 5.27 years (one half-life), 25% remains after 10.54 years (two half-lives), 12.5% remains after 15.81 years (three half-lives), and so on.
Step-by-step explanation:
You can figue out the rest.
