Quant, Math & Computer Science Puzzles for Interview Preparation & Brain Teasing
A collection of ~225 Puzzles with Solutions (classified by difficulty and topic)

Aug 20, 2010

Number of Sons


A man has two children. He says one of them is a son. What is the probability that the other one is also a son? (Hint: Answer is not 0.5 :P)

I have read this problem many times in many different forms. But still looks fresh :P


Read the wikipedia article of a famous and related problem (Link)


  1. There are only three cases now than four because GG is eliminated.
    Cases are: GB; BG; BB
    SO the required probability is: 1/3