(1) The time within which an act is to be done as provided in these rules shall be computed by excluding the first day and including the last, except that if the last day be Saturday, Sunday, or a legal holiday, the act may be done on the next succeeding regular business day. When the period of time prescribed or allowed is less than 11 days, intermediate Saturdays, Sundays and legal holidays shall be excluded in the computation.

(2) Computing time when serving by mail. Whenever a party has the right or is required to do some act or take some action within a prescribed period after the service of a notice or other paper upon him, or whenever such service is required to be made within a prescribed period before a specified event, and the notice or paper is served by mail, postmarking of the notice or paper on or before the prescribed period shall satisfy this rule.