10:20
`` Why , I had the tray -- with the mixed pieces -- '' `` Just a minute , '' interrupted Miss Allen . `` Miss Berg , what time did you ask permission to leave the floor ? '' `` At 10:15 , '' replied the other promptly . `` And the ring was lost , or missed , at 10:20 . You were not on the floor when it happened , at all . '' `` She ought to know her own business , '' snapped the detective . `` And I ought to know mine , '' replied Miss Allen .