(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 the act or the giving of the notice.
(B) The time within which an act is to be done as provided in this code or in any order issued pursuant to any ordinance, when expressed in days, shall be computed by excluding the first day and including the last; except that, if the last day is a Saturday, Sunday or holiday, it shall be excluded; and when the time is expressed in hours, the whole of Saturday, Sunday or a holiday, from midnight to midnight, shall be excluded.