If you answer both questions correctly, you will find out the numerical code to decrypt this paragraph from Minerva McGonagall's letter:
gtj gryu iutmxgzargzk eua ut ngbotm inuykt zu yzaje irgyyoigr rgtmagmky, yotik znkox osvuxzgtik oy latjgsktzgr zu znk zxgototm ul huzn sgmoiogty gtj sammrky.