# Can You Solve The Probability The Newborn Is A Boy? Many Fail This Interview Question

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## Description

This problem has been asked in job interviews. On the morning of January 1, a hospital nursery has 3 boys and some number of girls. That night, a woman gives birth to a child, and the child is placed in the nursery. On January 2, a statistician conducts a survey and selects a child at random from the nursery (including the newborn and every child from January 1). The child is a boy. What is the probability the child born on January 1 was a boy? There are a couple of neat counter-intuitive parts of this problem. Can you figure it out? Watch the video for a solution.

My blog post on this video

http://wp.me/p6aMk-4VP

Math StackExchange

http://math.stackexchange.com/questions/214680/simple-bayes-theorem-question

GlassDoor Interview Question For Susquehanna International Group, LLP

https://www.glassdoor.com/Interview/Hospital-has-three-boys-and-an-unknown-number-of-girls-A-mother-has-a-baby-A-nurse-picks-up-a-baby-at-random-and-it-is-a-QTN_223227.htm

Math By Matt (2 boys case)

https://matthewhr.wordpress.com/2013/04/08/probability-that-your-wife-had-a-boy/

Quora (2 boys case)

https://www.quora.com/What-interview-questions-would-be-typical-for-a-quantitative-finance-company-such-as-Jane-Street-Capital#

If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecisions

Connect on social media. I update each site when I have a new video or blog post, so you can follow me on whichever method is most convenient for you.

My Blog: http://mindyourdecisions.com/blog/

Twitter: http://twitter.com/preshtalwalkar

Facebook: https://www.facebook.com/pages/Mind-Your-Decisions/168446714965

Google+: https://plus.google.com/108336608566588374147/posts

Pinterest: https://www.pinterest.com/preshtalwalkar/

Tumblr: http://preshtalwalkar.tumblr.com/

Instagram: https://instagram.com/preshtalwalkar/

Patreon: http://www.patreon.com/mindyourdecisions

Newsletter (sent about 2 times a year): http://eepurl.com/KvS0r

My Books

"The Joy of Game Theory" shows how you can use math to out-think your competition. (rated 4/5 stars on 23 reviews) https://www.amazon.com/gp/product/1500497444

"The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias" is a handbook that explains the many ways we are biased about decision-making and offers techniques to make smart decisions. (rated 5/5 stars on 1 review) https://www.amazon.com/gp/product/1523231467/

"Math Puzzles Volume 1" features classic brain teasers and riddles with complete solutions for problems in counting, geometry, probability, and game theory. Volume 1 is rated 4.5/5 stars on 11 reviews. https://www.amazon.com/gp/product/1517421624/

"Math Puzzles Volume 2" is a sequel book with more great problems. https://www.amazon.com/gp/product/1517531624/

"Math Puzzles Volume 3" is the third in the series. https://www.amazon.com/gp/product/1517596351/

"40 Paradoxes in Logic, Probability, and Game Theory" contains thought-provoking and counter-intuitive results. (rated 4.9/5 stars on 7 reviews) https://www.amazon.com/gp/product/1517319307/

"The Best Mental Math Tricks" teaches how you can look like a math genius by solving problems in your head (rated 4.7/5 stars on 3 reviews) https://www.amazon.com/gp/product/150779651X/

"Multiply Numbers By Drawing Lines" This book is a reference guide for my video that has over 1 million views on a geometric method to multiply numbers. (rated 5/5 stars on 1 review) https://www.amazon.com/gp/product/1500866148/

My blog post on this video

http://wp.me/p6aMk-4VP

Math StackExchange

http://math.stackexchange.com/questions/214680/simple-bayes-theorem-question

GlassDoor Interview Question For Susquehanna International Group, LLP

https://www.glassdoor.com/Interview/Hospital-has-three-boys-and-an-unknown-number-of-girls-A-mother-has-a-baby-A-nurse-picks-up-a-baby-at-random-and-it-is-a-QTN_223227.htm

Math By Matt (2 boys case)

https://matthewhr.wordpress.com/2013/04/08/probability-that-your-wife-had-a-boy/

Quora (2 boys case)

https://www.quora.com/What-interview-questions-would-be-typical-for-a-quantitative-finance-company-such-as-Jane-Street-Capital#

If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecisions

Connect on social media. I update each site when I have a new video or blog post, so you can follow me on whichever method is most convenient for you.

My Blog: http://mindyourdecisions.com/blog/

Twitter: http://twitter.com/preshtalwalkar

Facebook: https://www.facebook.com/pages/Mind-Your-Decisions/168446714965

Google+: https://plus.google.com/108336608566588374147/posts

Pinterest: https://www.pinterest.com/preshtalwalkar/

Tumblr: http://preshtalwalkar.tumblr.com/

Instagram: https://instagram.com/preshtalwalkar/

Patreon: http://www.patreon.com/mindyourdecisions

Newsletter (sent about 2 times a year): http://eepurl.com/KvS0r

My Books

"The Joy of Game Theory" shows how you can use math to out-think your competition. (rated 4/5 stars on 23 reviews) https://www.amazon.com/gp/product/1500497444

"The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias" is a handbook that explains the many ways we are biased about decision-making and offers techniques to make smart decisions. (rated 5/5 stars on 1 review) https://www.amazon.com/gp/product/1523231467/

"Math Puzzles Volume 1" features classic brain teasers and riddles with complete solutions for problems in counting, geometry, probability, and game theory. Volume 1 is rated 4.5/5 stars on 11 reviews. https://www.amazon.com/gp/product/1517421624/

"Math Puzzles Volume 2" is a sequel book with more great problems. https://www.amazon.com/gp/product/1517531624/

"Math Puzzles Volume 3" is the third in the series. https://www.amazon.com/gp/product/1517596351/

"40 Paradoxes in Logic, Probability, and Game Theory" contains thought-provoking and counter-intuitive results. (rated 4.9/5 stars on 7 reviews) https://www.amazon.com/gp/product/1517319307/

"The Best Mental Math Tricks" teaches how you can look like a math genius by solving problems in your head (rated 4.7/5 stars on 3 reviews) https://www.amazon.com/gp/product/150779651X/

"Multiply Numbers By Drawing Lines" This book is a reference guide for my video that has over 1 million views on a geometric method to multiply numbers. (rated 5/5 stars on 1 review) https://www.amazon.com/gp/product/1500866148/

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