Problem 6.226

The specific activity of a preparation consisting of radioactive $\mathrm{Co}^{58}$ and nonradioactive $\mathrm{Co}^{59}$ is equal to $2.2 \cdot 10^{12} \mathrm{dis} /(\mathrm{s} \cdot \mathrm{g})$. The half-life of $\mathrm{Co}^{58}$ is 71.3 days. Find the ratio of the mass of radioactive cobalt in that preparation to the total mass of the preparation (in per cent).