The couple has two children and one is known to be boy,
The probability that the other is boy will be 
Total outcomes are 3 ,
The first child is a boy, the second girl
The first child is a girl, the second boy
The first child is a boy, second boy
The favourable outcome is one,
Thus, the probability that the other is boy will be
Hence, the correct option is a.
A couple has 2 children. What is the probability that both are boys. If it is known that one of them is a boy?
A. 
B. 
C. 
D. 
