Section 10. A vote passed at any representative town meeting authorizing the expenditure of twenty thousand dollars or more as a special appropriation, or establishing a new board or office or abolishing an old board or office or merging two or more boards or offices, or fixing the term of office of town officers, where such term is optional, or increasing or reducing the number of members of a board, or adopting a new by-law, or amending an existing by-law, shall not be operative until after the expiration of seven days, exclusive of Sundays and holidays, from the dissolution of the meeting. If, within said seven days, a petition, signed by not less than three per cent of the registered voters of the town, containing their names and addresses as they appear on the list of registered voters, is filed with the selectmen asking that the question or questions involved in such a vote be submitted to the registered voters of the town at large, then the selectmen, after the expiration of five days, shall forthwith call a special meeting for the sole purpose of presenting to the registered voters at large the question or questions so involved. The polls shall be opened at two o'clock in the afternoon and shall be closed not earlier than eight o'clock in the evening, and all votes upon any questions so submitted shall be taken by ballot, and the check list shall be used in the several precinct meetings in the same manner as in the election of town officers. The questions so submitted shall be determined by a majority vote of the registered voters of the town voting thereon, but no action of the representative town meeting shall be reversed unless at least twenty per cent of the registered voters shall so vote. Each question so submitted shall be in the form of the following question, which shall be placed upon the official ballot:?''Shall the town vote to approve the action of the representative town meeting whereby it was voted (brief description of the substance of the vote and by what vote thereon if such vote was tabulated)?'' If such petition is not filed within said period of seven days, the vote of the representative town meeting shall become operative and effective upon the expiration of said period. Absent voter ballots shall be used at such election in accordance with the provisions of chapter fifty-four.