If you answer both questions correctly, you will find out the numerical code to decrypt this paragraph from Minerva McGonagall's letter:
Nuey, zil chmnuhwy, nby mcgjfy mjyff nbun sio hyyx ni omy ch ilxyl ni mqcnwb ih u fcabn. Cz cn’m willywnfs jlihiohwyx, cn qcff qile chmnuhnfs; biqypyl, cz gcmjlihiohwyx, migyihy gus yhx oj bupcha nblyy byuxm.