[IQ Challenge]

Q1. If a couple has two children (born 1 year apart and have different names), given that at least one of them is a girl,

what is the probability that both children are girls?

Q2 If a couple has two children (born 1 year apart and have different names), given that at least one of them is a girl,

and that this girl is named Ah Lian, what is the probability that Ah Lian's sibling is also a girl?

Q3 Why are the correct answers to the Q1 & Q2 different?