Section 24. The aldermen in cities, except where city charters provide otherwise, and the selectmen of towns divided into voting precincts, shall, twenty days at least before the biennial state or annual or biennial city election and ten days at least before any special election of a state or city officer therein, designate the polling place for each voting precinct and cause it to be suitably fitted up and prepared therefor. In a city or town which has provided voting booths such booths may be placed in the public ways of such city or town, provided said ways are left reasonably safe and convenient for public travel. It shall be in a public, orderly, and convenient portion of the precinct; provided, however that if the aldermen or selectmen determine that the public convenience would be better served, the aldermen may designate a polling place in an adjacent precinct of a city, and the selectmen may designate a polling place in another precinct of a town or may house all polling places in a single building within the town. In any city or town, if the polling places for two or more precincts are located in the same building and the total number of registered voters in any such two or more precincts does not exceed three thousand, only one set of election officers need be appointed for such precincts, but separate ballot boxes and voting lists for each precinct shall be used. If, in a town of five precincts or less, all of which are located in one building, the selectmen so vote, only one warden need be appointed to supervise all such precincts, and the number of inspectors shall be determined by the selectmen, without disturbing the balance between the political parties. There shall, however, be one clerk appointed for each such precinct. Alcoholic beverages shall not be sold in any portion of a building which is designated as a polling place, during voting hours or while ballots are being counted therein. When the polling places have been designated in the city of Boston, the board of election commissioners of said city may post in such places as it may determine a printed description of the polling places designated and may give further notice thereof; and when the polling places have been designated in any other city or in any town, the aldermen of such city in at least five public places in each precinct thereof, and the selectmen of such town in at least three public places in each precinct thereof, shall forthwith post a printed description of the polling places designated and may give further notice thereof. When a polling place in a voting precinct is changed from one location to another, the board of election commissioners in the city of Boston, the aldermen in any other city or the selectmen in any town shall cause printed descriptions of such polling place to be posted in such public places in such precinct as they determine and shall give notice by mail to each residence of one or more registered voters therein.