History of Space Exploration: Chapter 9, Exercise 3 — Possible Solution
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THE FIGURES
5,352 sols (15 years) in one article, 5,111 sols (14 years, 138 days) in
another. The difference is 241 sols and neither article explains it.

HANDLING
Prefer 5,111, which matches the 57-times design-life figure and the
January 2004 to June 2018 dates, name the source, and note that another
article gives a larger number. Do not quote both as if they agreed.