Art of Problem Solving: 2015 AMC 12 A #25

Art of Problem Solving's Richard Rusczyk solves 2015 AMC 12 A #25.

[@nicolebright5964]

As usual Mr Rusczyk makes an extremely hard question seem super easy.

[@wg9601]

Farey sequence in ford circles using geometry and algebra. Lovely! Great vid, as always!

[@emilycoulter7775]

The wording is so ambiguous the question is impossible until you show a picture of what the writer is trying to communicate

[@nicolebright5964]

Eh not really, it was pretty clear but a bit complex. The U sign was a bit unnecessary as I don't think it ever appeared on an AMC/AIME before and definitely doesn't appear on the average high school curriculum afaik, it probably scared a lot of people from doing this problem.

[@realquarterb5344]

Yeah, the U was a bit unnecessary, but that was exactly the point. The problem in itself was fairly easy, just under a huge layer of words and symbols which makes it "look" difficult.

[@kesselmines]

Love your videos, they provide a nice morning problem for me to solve each day! Thank you 😊

[@bondgavin100]

You are a God

[@someperson5137]

I am so grateful that my parents found this channel for me

[@toebel]

join the aops forums if you haven't already

[@toebel]

@@SomeRandomGtaDude-zl3us If you like math, it's good to have people to talk to about it, especially when those people are just as interested in it as you. You can also expose yourself to a lot of ideas that you might not have thought about by yourself

[@alexwu7615]

Cool Solution, Rusczyk

[@zmaj12321]

I feel proud for getting this right

[@AntonioMac3301]

This is such a complicated notation. I dont even understand what the problem is saying