Passage: Twelve Senators from each state are elected for six-year terms, using proportional representation and the single transferable vote (known in Australia as "quota-preferential voting": see Australian electoral system), with half elected every three years. In addition to the state Senators, two senators are elected by voters from the Northern Territory (which for this purpose includes the Indian Ocean Territories, Christmas Island and the Cocos (Keeling) Islands), while another two senators are elected by the voters of the Australian Capital Territory (which for this purpose includes the Jervis Bay Territory). Senators from the territories are also elected using preferential voting, but their term of office is not fixed;  it starts on the day of a general election for the House of Representatives and ends on the day before the next such election.

Question: How long is the longer term a senator can serve?
six-year terms