If the half-life of a sample of a radioactive substance is 30 seconds, how much would be left after 60 seconds? A. one-fourth B. half C. one-eighth D. You would need to know how many atoms you are starting with.

[latex]m=m_{0}*(\frac{1}{2})^{\frac{60}{30}}\\\\ m=m_{0}*(\frac{1}{2})^{2}\\\\ m=\frac{1}{4}m_{0}[/latex] If the half-life of a sample of a radioactive substance is 30 seconds, how much would be left after 60 seconds? A. one-fourth