So I've been attempting to try and answer question A2 on the following: http://www.imo-official.org/problems/IMO2013SL.pdf
I haven't looked at the solution, so I'm not really sure where to start. The only thing I can think of so far is denoting a variable to be the distance between the numbers within the set, and then coming up with a formula such that the largest distance between the numbers is say x-y where x is the largest number and y the smallest.
Any help appreciated.
IMO past problem Watch
- Thread Starter
- 20-07-2014 00:34
- 20-07-2014 19:41
It's been a long time since I did anything like this but here's a first thought of one possible line you could take. Clearly if you can find a,b,c,d such that a-b =c-d then the problem is done. So you should assume that this condition is false and see what that means.Spoiler:Showonce you know what these sets look like the next step could be, for example, that you assume WLOG that a-b<c-d (why?) and remove the mod sign
A second first approach could be to ask yourself what the RHS means specifically.
Posted from TSR MobileLast edited by LightBlueSoldier; 20-07-2014 at 19:48.