This problem is adapted from a national math competition exam in France. Special thanks this month to: Michael Anvari, Robert Zarnke, Fiona Harper, Kyle, Jamal Jackson. Mike Robertson. Thanks to all supporters on Patreon! http://www.patreon.com/mindyourdecisions

Sorry for the repost! In my original video (https://youtu.be/_2GPAzpSyDQ) I had a calculation mistake around 7:10 in method 3. I immediately took down the video and have posted a correction within 24 hours. I thank Inspired and Филипп Лыков for letting me know!

0:00 Problem
0:44 Method 1
3:52 Method 2
6:11 Method 3

I learned about methods 2 and 3 on Quora
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