It is know that Japan experiences about 500 earthquakes per year huge enough, to be noticed on the Richter scale. However, of those earthquakes we know that a deadly earthquake happens only on average once per year

1. What is the probability of waiting at least three months after the last huge earthquake to hit, to be a deadly one?
2. Suppose, that a deadly earthquake hasn't been noticed in the last 8 months. What is the probability that we will not notice a deadly earthquake for 3 more months?
3. What is the the probability that we have to wait at least 6 years for the fourth deadly earthquake to strike?