premise: The Path Between the Seas: The Creation of the Panama Canal, 1870–1914 (1977) is a book by the American historian David McCullough, published by Simon & Schuster. It won the U.S. National Book Award in History, the Francis Parkman Prize, the Samuel Eliot Morison Award and the Cornelius Ryan Award.
hypothesis: It took workers a total of forty four years to complete the construction of the Panama Canal. 
reason: When you subtract 1870 from 1914, you get 44 years. That is the time frame reference by the book The Creation of the Panama Canal. The AI could not do the math to come up with a total number of years.