13. (1) The meetings of the Council and the Executive Committee shall be held at such times and at such places as may be prescribed by rules: Provided that until rules are made in this behalf such meetings shall be convened by the Chairman. (2) Twenty-one members, in the case of a meeting of the Council, and seven members, in the case of a meeting of the Executive Committee, shall constitute a quorum. (3) A decision at a meeting of the Council and of the Executive Committee shall be taken by a majority of votes of the members present and voting, but the person presiding shall not vote except when there is an equality of votes, in which case he shall exercise a casting vote. ¹[(4) The Chairman shall preside over the meetings of the Council and, in his absence, the members of the Council present shall elect a Chairman from amongst them to preside over that meeting. (4A) The Chairman, or in his absence, the Vice-Chairman shall preside over the meetings of the Executive Committee, and in the absence of both of them, the members of the Executive Committee present shall elect a Chairman from amongst them to preside over that meeting.] (5) No proceeding or decision of the Council or the Executive Committee shall be invalid by reason of the existence of any vacancy or defect in the constitution of the Council or the Executive Committee.