This thread is dedicated for a marathon on relatively easy problems. The rules are similar to the Geo Marathon or the Combi Marathon, just with a focus on easier problems.
We'll start by posting problems, and someone else will post the solution. If someone solves a problem, they should post a pretty solution, and they have the honor of posting the next problem. If the solver of the previous problem doesn't post a new problem along with his solution, anyone else can post a new problem. If no one solves a problem within 48 hours of posting, the problem poster should provide the solution or a link to the solution. Then we'll jump to the next problem.
The problem difficulty should be at most the hardest found in BDMO. The focus is on easy problems, so even problems of BDMO National #1 level are welcome. Ideally most of the problems will be somewhere between these two extremes, and help out all the people still looking to break at BDMO nationals.
2. Try to use LaTeX code
3. Be sure about your provided problem.
There are two extra rules I will be enforcing about this thread:
[*] No posting problems above the difficulty ceiling. An honest mistake won't be punished, but if you repeatedly do this to troll people actions will be taken against you. If you want to know the solution of a difficult problem, please post it in a separate thread in the relevant section.
[*] This thread is open to all, from new math enthusiasts to the very 'buddha' campers who want to brush up basic skills. Judging/flaming anyone for participation in this marathon is STRICTLY FORBIDDEN. If anyone is found doing this, they will suffer strict punishment.