Bruce banner is studying a new element called asgardium. He finds that asgardium emits gamma radiation and has a half-life of 15 days. He knows that is he is exposed to gamma radiation above an average of 1.0 counts per second, he will turn into the hulk. If the sample he is waiting to study emits gamma radiation at an average of 8.0 counts per second, how many days does he need to wait to begin studying this sample