Question

peter selects a month for his holiday.find the probability that will be april or december.assume that all months have an equal opportunity of being selected

Answer 1

$$P(April)=\dfrac{1}{12}, P(December)=\dfrac{1}{12}$$

These two events  are disjoint, then the probability of either event is the sum of the probabilities of the two events:

$$P((April)\cup (December))$$

$$=P(April)+P(December)$$

$$=\dfrac{1}{12}+\dfrac{1}{12}=\dfrac{1}{6}$$

The probability that will be april or december is $\dfrac{1}{6}.$