The affairs of such association shall be managed by not less than 5, nor more than 9 trustees to be chosen by the members thereof and to hold office for 1 year and until their successors shall be chosen; a treasurer shall be appointed from the number of trustees, and the other regular officers shall be members of the association. A majority of the trustees shall be a quorum to transact business, and they may adopt such by-laws not repugnant to this act or to such articles of association as they may see fit and change the same at pleasure.