The problem should be : probably that both are boys, else probability one of them is a boy given on is a boy =1. The answer to corrected problem is 13/27
For those who didn't get Try making a sample space 1st child = {Boy, Girl} 1st child born on {Sun,Mon,Tue,Wed,Thu,Fri,Sat} 2nd child = {Boy, Girl} 2nd child born on {Sun,Mon,Tue,Wed,Thu,Fri,Sat}
with the constraint one being boy born on Sunday {(BSu,BSu),(BSu,BMo),(BSu,BTu),(BSu,BWe)(BSu,BTh)(BSu,BFr)(BSu,BSa)(BMo,BSu)(BTu,BSu)(BWe,BSu)(BTh,BSu)(BFr,BSu)(BSa,Bsu} Another 7 cases when 1st is boy and born on Sunday with 2nd as girl born on any 7 days Another 7 cases when 2nd is boy and born on Sunday with 1st as girl born on any 7 days
The problem should be : probably that both are boys, else probability one of them is a boy given on is a boy =1.
ReplyDeleteThe answer to corrected problem is 13/27
For those who didn't get
ReplyDeleteTry making a sample space
1st child = {Boy, Girl}
1st child born on {Sun,Mon,Tue,Wed,Thu,Fri,Sat}
2nd child = {Boy, Girl}
2nd child born on {Sun,Mon,Tue,Wed,Thu,Fri,Sat}
with the constraint one being boy born on Sunday
{(BSu,BSu),(BSu,BMo),(BSu,BTu),(BSu,BWe)(BSu,BTh)(BSu,BFr)(BSu,BSa)(BMo,BSu)(BTu,BSu)(BWe,BSu)(BTh,BSu)(BFr,BSu)(BSa,Bsu}
Another 7 cases when 1st is boy and born on Sunday with 2nd as girl born on any 7 days
Another 7 cases when 2nd is boy and born on Sunday with 1st as girl born on any 7 days
Thus, Ans = 13/27