probabiblity 1/4 when extracting 2 balls from a urn of yellow and greens
Source: 2009 Swedish Mathematical Competition p3
April 27, 2021
probabilitycombinatorics
Problem Statement
An urn contain a number of yellow and green balls. You extract two balls from the urn (without adding them back) and calculate the probability of both balls being green. Can you choose the number of yellow and green balls such that this probability to be ?