In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
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Question: Context: Serra made one CART Champ Car start in 1985 at the Portland International Raceway for Ensign Racing but suffered an engine failure. Link Information: Ensign entered Formula One in , with backing from pay driver, Rikky von Opel. Von Opel had driven for the team in Formula Three in 1972 and won the Lombard North Central, British Formula Three Championship that year. Based upon that success, von Opel commissioned a Formula One chassis. Their first season was not successful, von Opel only finished two races and the team's best result that season was 13th at the 1973 British Grand Prix. Question: How long had Ensign Racing been in business when Serra made one CART Champ Car start at the Portland International Raceway?

Answer: Answer: 12


Question: Context: Murdoch appointed Frank Giles to be the editor of The Sunday Times. Link Information: Frank Thomas Robertson Giles (31 July 1919 – 30 October 2019 Question: What is the age difference between Rupert Murdoch and the person he appointed editor of the Sunday Times?

Answer: Answer: 12


Question: Context: Serco operates the Santander Cycles scheme (for Transport for London) and the NorthLink Ferries Northern Isles lifeline ferry service in Scotland. Link Information:  Since July 2012, it has been operated by international services company Serco. Question: How many years has Serco been operating the NorthLink Ferries?

Answer:
Answer: 7