Whenever 100 or more taxpaying electors of any city having a library tax in force shall file a petition with the Mayor asking that such tax be raised, reduced or abolished, the question shall be submitted to the qualified electors at a general or special election. Such petition must be filed at least thirty days prior to the election at which it will be submitted to the voters. The ballot shall follow, as far as practicable, the form set forth in Section 1 hereof. The result shall be certified and proclaimed, as provided in Section 2 hereof, and the result as proclaimed shall be conclusive unless attacked in the courts within thirty days. Subject to the limitations of Section 5(e) hereof, the tax shall be lowered, raised or abolished, as the case may be, according to the majority of the qualified electors voting on the question of such election. If lowered or raised, the revised tax shall thereafter be continually levied and collected and the proceeds used in the manner and for the purposes as provided in Section 2 hereof. [As amended by Const. Amend. 72, § 2.]