We are numbering the rows and columns of a $29 \text{x} 29$ chess table with numbers $1, 2, ..., 29$ in order (Top row is numbered with $1$ and first columns is numbered with $1$ as well). We choose some of the squares in this chess table and for every selected square, we know that there exist at most one square having a row number greater than or equal to this selected square's row number and a column number greater than or equal to this selected square's column number. How many squares can we choose at most?
Problem
Source: Turkey Junior National Olympiad 2021 P2
Tags: combinatorics, combinatorics proposed
Jalil_Huseynov
07.01.2022 21:32
$29$ used in Turkey MO for seniors P1 too. Does it has special meaning? Because generally it is given as general $n$ or as a year of olympiad. But what about $29$?
@below Thank you for information!
Attachments:
CamScanner 01-07-2022 22.15.pdf (173kb)
BarisKoyuncu
07.01.2022 21:40
Jalil_Huseynov wrote:
$29$ used in Turkey MO for seniors P1 too. Does it has special meaning? Because generally it is given as general $n$ or as a year of olympiad. But what about $29$?
This year's exam is the $29$th Junior National Olympiad.
sttsmet
03.06.2022 12:39
Sorry but I think the statement is incomplete. electrovector wrote: We choose some of the squares in this chess table and for every selected square, we know that there exist at most one square having a row number greater than or equal to this selected square's row number I think it should be "we know that there exists at most one selected square..." Otherwise the problem makes no sense!!