If you answer both questions correctly, you will find out the numerical code to decrypt this paragraph from Minerva McGonagall's letter:
Klwbaf Olhktpzaylzz: Tpulych TjNvuhnhss
(Vykly vm Tlyspu, Zljvuk Jshzz, Nyhuk Zvyjlylzz, Joplm Thnp vm aol Dpglunhtva, Pualyuhapvuhs Jvumlklyhapvu vm Dpajolz)