5
Part of 2015 May Olympiad
Problems(2)
65 points in a plane(combinat)
Source: May Olympiad(Olimpiada de Mayo) 2015
10/10/2017
If you have points in a plane, we will make the lines that passes by any two points in this plane and we obtain exactly distinct lines, prove that least points are collinears!!
geometrycombinatorics
friendships among 26 people, May Olympiad (Olimpiada de Mayo) 2015 L1 P5
Source:
9/26/2021
Twenty-six people gather in a house. Alicia is friends with only one person, Bruno is friends with two people, Carlos is a friend of three, Daniel is four, Elías is five, and so following each person is friend of a person more than the previous person, until reaching Yvonne, the person number twenty-five, who is a friend to everyone. How many people is Zoila a friend of, person number twenty-six?Clarification: If is a friend of then is a friend of .
combinatorics