420.505 Meetings; quorum; voting.—The powers of the corporation shall be vested in the members of its board of directors in office from time to time. Five members of the board shall constitute a quorum for the purpose of conducting its business and exercising its powers and for all other purposes. Action may be taken by the board upon an affirmative vote of a majority of the members present, provided that no action shall be taken by an affirmative vote of less than four members.