5
Problems(2)
exist 1000 consecutive numbers, none divides by sum of its digits
Source: 239 2011 J6
5/18/2020
Prove that there exist 1000 consecutive numbers such that none of them is divisible by its sum of the digits
number theory
20 blue points on circle, 1123 contain 10 red
Source: 239 2011 J5
5/18/2020
There are 20 blue points on the circle and some red inside so no three are collinear. It turned out that there exists triangles with blue vertices having 10 red points inside. Prove that all triangles have 10 red points inside
combinatorics