Meetings of the Board shall be held at the call of the Chairperson, and at such other times as the Board may determine. Such Chairperson, or in the absence of the Chairperson, the acting Chairperson, may administer oaths and compel the attendance of witnesses. All meetings of the Board shall be open to the public. The Board shall keep minutes of its proceedings, showing the vote of each member on each question, or if absent or failing to vote, indicating such fact, and shall keep records of its examinations and other official actions, all of which shall be immediately filed in the office of the Board and shall be a public record. The presence of three (3) members shall be necessary to constitute a quorum. A majority of the members of the Board of Adjustment shall be persons representing the public at large and shall not be involved in the business of purchasing or selling real estate.