Physics

Problem

A container of spent

^{131}\text{I}

solution shows an activity of

8.0\,\text{mCi}

today. Regulations permit disposal only when its activity falls below

0.25\,\text{mCi}

. The half-life of

^{131}\text{I}

8.0\,\text{days}

. For how many days must the container be stored before disposal is allowed?