Solution
Assume denotes boy and denote girl.
Then, the sample space of the given experiment is Let be the event that ‘both are girls’.
(i) Let be the event that ‘the youngest is a girl’.
Now,
Now, we know that by relation of conditional probability,
and (ii)]
(ii) Assume be the event that ‘at least one is a girl’.
Now,
Now, we know that by relation of conditional probability,