Problem of the Week

Week of February 25 2019

Friday, March 1, 2019

The Problem: In a certain tribe, all families want girls. They keep having babies until a girl is born. What is the expected ratio of boys and girls in this tribe assuming girls and boys are equally likely to be born?

Hint: Focus separately on 1st born, 2nd born,etc.

Solution: 1st born, 2nd born, 3rd born, and so on, are all equally likely to be boys or girls so the expected ratio of boys to girls is .

Contact:

Maria Cristina Manabat
tmanabat@sandiego.edu
(619) 260-4706

College of Arts and Sciences

Contact Us Email

Visit Campus Map

Founders Hall
5998 Alcalá Park
San Diego, CA 92110