n boys and n girls in a row, students get candies
Source: Vietnamese National Mathematical Olympiad 2012-P4
February 8, 2012
combinatorics unsolvedcombinatorics
Problem Statement
Let be a natural number. There are boys and girls standing in a line, in any arbitrary order. A student will be eligible for receiving candies, if we can choose two students of opposite sex with standing on either side of in ways. Show that the total number of candies does not exceed