Question 143705
Assuming that the probability of rain today and tomorrow are INDEPENDENT (that is, rain probabilities are in no way related, as by storm systems or hurricanes, etc.), the probability of rain today AND tomorrow is


P(Rain today AND tomorrow) = P(Rain today)*P(Rain tomorrow) = .3*.6 = .18.


P(Rain doday OR tomorrow) = P(Rain today) +P(Rain tomorrow) - P(Rain today and tomorrow)
=.3 + .6-.18 = .90-.18 = .72 or 72%


R^2