co Radioactive element $A A$ can decay to either element $B B$ or element $C C$. The decay depends on chance, but the ratio of the resulting number of $B B$ atoms to the resulting number of $C C$ atoms is always $2 / 1$. The decay has a half-life of $8.00$ days. We start with a sample of pure $A A$. How long must we wait until the number of $C C$ atoms is $1.50$ times the number of $A A$ atoms?