Answer :
See below the theee of possibilities:
BBBB
BBBG
BBGB
BBGG
BGBB
BGBG
BGGB
BGGG
GBBB
GBBG
GBGB
GBGG
GGBB
GGBG
GGGB
GGGG
There are 16 differents possibilities.
In 11 of them have at least 2 boys
So probability is 11/16
BBBB
BBBG
BBGB
BBGG
BGBB
BGBG
BGGB
BGGG
GBBB
GBBG
GBGB
GBGG
GGBB
GGBG
GGGB
GGGG
There are 16 differents possibilities.
In 11 of them have at least 2 boys
So probability is 11/16