If the requirement is specifically for 67% (or more) approval, then that would be 11 votes; 10 votes of 15 units is 66.66666[etc.] percent, or just short of that. A requirement for 67% approval is a requirement for more than 2/3 approval; 10 of 15 is 2/3.However, note that the above is based on general principles of construction or interpretation; the law does not definitively answer this question. It is possible that--especially if there is some other evidence in the governing agreements showing that a 2/3 approval was what was contemplated--that a court could come to a contrary interpretation in this specific case.