Hello every .
Now, exactly years ago, Mongolia held its first direct presidential elections. To celebrate this, I would like to propose a new contest:
Rules: A member posts a link to a problem of their choice. Then, another member who has solved that problem must comment in the solutions section to prove that he has solved the said problem, and can then choose another challenging problem for others to solve. One may not nominate two problems in a row, however, the problem's author is allowed to participate.
The point of this is to show some challenging problems which you wouldn't otherwise want to solve/ try. The person who has nominated the most problems, as well as the problem author whose problems were selected the most times, will win the contest.
The contest will end when one person has nominated problems. No further entries will be accepted.
The first problem is my Cards. Why Does It Have To Be Cards?. Try and solve it and then post a link to another problem!
Do like and reshare, so that more people can participate.
Note: The problems must either be in Algebra, Number Theory, Combinatorics, Calculus or Geometry.