Note: Most of these problems will be dealing with exponential growth/decay. Such problems can all be mod-eled with y = y0ekt where y is measuring whatever quantity is growing or decaying, y0 is the original amount of what’s being measured, t is time, and k is the growth/decay rate (per the time period that t is being mea-sured in), which is often given as a percentage. Radioactive Iodine-131, a daughter product of uranium decay and nuclear reactions, has a half-life of 8 days. How long does it take to reduce an initial amount of Iodine-131 to 1% of the initial amount?

(Answer is 53.2 years) I just want to know how to set up the problem to solve this equation.