When a petition, signed by electors of any county, city or township equal in number to not less than five percent (5%) of the qualified electors of such county, incorporated city or township, shall be presented to the board of county commissioners of such county, the governing body of such city, or the trustee, clerk and treasurer of such township, asking that a vote be taken upon the question of building, purchasing or repairing a bridge such officers shall, within ten (10) days after the presentation of such petition, call an election as provided by law to vote on such proposition.