If you answer both questions correctly, you will find out the numerical code to decrypt this paragraph from Minerva McGonagall's letter:
Kc iye uxyg, kd Ryqgkbdc cdenoxdc cdeni dro celtomd yp mrkbwc pyb cofobkv iokbc kxn, dy ny drkd, droi eco dro Cdkxnkbn Lyyu yp Czovvc.