In Chelsea square, there are two mansions M1 and M2. Both M1 and M2 have two children each.
In Mansion M1, The boy plays for Chelsea youth academy and the other child play table tennis.
In Mansion M2, The boy recently joined the school and they just had a newborn in the home
Can you prove that probability of M1 having girl child is more than that of M2?
Solution:
In Mansion M2, we know that older child is boy, therefore there are two cases
Older Younger
Boy Girl
Boy Boy
Probability of at least one girl child: 1/2 => 50%
In Mansion M1 there are three cases
Older Younger
Boy Girl
Boy Boy
Girl Boy
Probability of at least one girl child: 2/3 => 66.67%