### Supposedly a friend of yours has 2 children and at least one of them is a boy. What is the probability that the other is also a boy?

---------------------------------------------------------------------------------------------------------------------------------------- Their explanation:Byjus

answer according to their approach is **1/3**.

**My approach**:

le the boy child be represented as B and girl as G ,younger child as 2 and elder child as 1.

So total outcomes are:((B1,B2),(B1,G2),(G1,B2),(G1,G2)).

so the known boy can be B1 or B2.

the probability of boy being elder child and he having a brother is (B1,B2)=(1/2)*(1/2).

the the probability of boy being younger child and he having a brother is (B1,B2)=(1/2)*(1/2).

so final probability =1/4+1/4=**1/2**.