Poisson Probability Distribution

1.Radioactive atoms are unstable because they have too much energy.When they release their extra energy, they are said to decay.When studying cesium -137, a nuclear engineer found that over 365 days, 1,000,000 radioactive atoms decayed to 977,287 radioactive atoms; therefore 22,713 atoms decayed during 365 days.Find the mean number of radioactive atoms that decayed in day.Find the probability that on a given day, exactly 50 radioactive atoms decayed.