These two questions are not equivalent.

Q1: I looked at only one of a pair of two randomly selected children and it was a girl. What is the probability the other I didn’t see is a girl?

Q2: I looked at both of two randomly selected children and at least one of the pair of children is a girl. What is the probability the other is also a girl?

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zeroonetwothree 4 days ago | parent [-]

There is no “the other” in the original question. Introducing that completely changes the meaning.

	▲	in_cahoots 4 days ago \| parent [-]
		The other part doesn't change anything at all. Here you go: Q1: I looked at only one of a pair of two randomly selected children and it was a girl. What is the probability there are two girls? Q2: I looked at both of two randomly selected children and at least one of the pair of children is a girl. What is the probability there are two girls?