(A) In all cases where an ordinance requires an act to be done in a reasonable time or requires reasonable notice to be given, reasonable time or notice shall be deemed to mean the time which is necessary for a prompt performance of that act or the giving of that notice.
(B) The last day of the period so computed is to be included, unless it is a Saturday, Sunday or legal holiday, in which event the period runs until the end of the next day which is not a Saturday, Sunday or legal holiday.