This question my son asked me on Purim (I don’t have an answer to it) during yeshivas Mordechai hatzaddik (so I wasn’t drunk yet)
רש״י says צומו עלי was י״ד- ט״ז (probably from a Gemara or medrash) so if that was the case בסוף שלשת ימים was ט״ז but in the הגדה at נרצה says that נדדה שנת המלך was the first night of Pesach so how does it work out?