You will be given a definition of a task first, then some input of the task.
In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.

Passage: Stren studied at Lillehammer Latin- og Realskole, at Qvams skole in Christiania and at the Swiss Federal Institute of Technology Zurich from 1862 to 1865. In 1866 he started working as a draftsman for Kanalvsenet, the body for exploitation of Norwegian water resources, and held various positions at Kanalvsenet over a period of 41 years. He ended his career as manager for the Bandak-Norsj Canal from 1891 to 1907. The boat locks of the Bandak-Norsj Canal could lift boats with a length of up to 100 feet. The canal became an important water transport system, and also a tourist destination. Stren was a counsellor for industrialist Sam Eyde, the founder and first mangager of Norsk Hydro, who acquired rights for exploiting waterfalls for hydroelectric power. Stren published maps and overviews of water resources in Norway, such as his map from 1904. He was the first editor of the magazine Norsk Teknisk Tidsskrift, which he edited from 1883 to 1886. He was also a proponent for the construction of the Holmenkoll Line, and chaired the board of directors for ten years from 1896. He was decorated Knight of the Royal Norwegian Order of St. Olav in 1893.
Link Information: was built in 18541861 Answer: 7
Output:
How many years did it take to build the canal that Stren worked at from 1891 to 1907?