Regular meetings of the city council of a city of the second class shall be held at such times as the city council may provide by ordinance. A majority of all the members elected to the city council shall constitute a quorum for the transaction of any business, but a fewer number of members may adjourn from time to time and compel the attendance of absent members. When the city council consists of four members as established by ordinance or home rule charter, the mayor shall be deemed a member of the city council for purposes of establishing a quorum when the mayor’s presence is necessary to establish the quorum. Unless a greater vote is required by law, an affirmative vote of at least one-half of the elected members shall be required for the transaction of any business.