At least 10 days before the time fixed for the hearing the board of supervisors shall publish a notice of the hearing by one insertion in the newspaper circulated in the district which the board believes will best serve to give notice to the inhabitants of the district of the proposed withdrawal of territory. The notice shall also be posted at least one week prior to the time fixed for the hearing in three public places within the district, one of which shall be within the portion of the district proposed to be withdrawn.