[HPMOR Ch. 114] The true solution involves time travel

Created by dain on 2015-03-02; known on 2015-03-03; judged wrong by dain on 2015-03-03.

• dain estimated 50% on 2015-03-02
• Chri estimated 15% on 2015-03-02
• iwakun estimated 10% on 2015-03-03
• dain   judged this prediction wrong on 2015-03-03.