11. (1) Meetings of the Board shall be convened by the Governor at least six times in each year and at least once in each quarter. (2) Any three Directors may require the Governor to convene a meeting of the Board at any time and the Governor shall forthwith convene a meeting accordingly. ¹[(3) The Governor or, if for any reason he is unable to attend, the Deputy Governor nominated under sub-clause (b) of clause (3) of Article 9, shall preside at meetings of the Board and in the event of any equality of votes, shall have a second or casting vote. In case the Deputy Governor is also unable to attend for any reason, any other Director, authorised by the Governor, shall preside over the meeting of the Board and shall have a second or casting vote.] (4) No act or proceedings of the Board shall be questioned on the ground merely of the existence of any vacancy in, or any defect in the constitution of, the Board.