In a family having three children, there may be no girl, one girl, two girls or three girls. So, the probability of each is 1/4. Is this correct? Justify your answer.

No, the probability of each is not 1/4 because the probability of no girl in three children is zero and probability of three girls in three children is one.

Justification

So, these events are not equally likely as outcome one girl, means gbb, bgb, bbg - three girls’ means “ggg” and so on.