A quorum is a moving target. Your HOA may be required to reach a 30 percent quorum in one situation, a 66 percent in another, or 51 percent in yet another. You must read your documents carefully.
Black’s Law Dictionary, defines 'quorum' as:
quorum, n. The minimum number of members (usu. a majority) who must be present for a body to transact business or take a vote.
II. A QUORUM FOR AN HOA MEMBERS’ MEETING: