Let:
Event A: Rain
Event B: mostly cloudly
Then, the probability (P) of the events occurring is:
P(A) = 0.71
P(B) = 0.75
P(A and B) = 0.85
Since the events are non-mutually exclusive, P(A or B) can be found using the formula below:
The probability that it will be mostly cloudy or it will rain is P(A or B), substituting the values, we have:
Answer: 61%.