Final answer:
To find out how many pages were cut, subtract the number of pages in the finished book from the original number of pages.
Step-by-step explanation:
To find out how many pages were cut, we need to subtract the number of pages in the finished book from the original number of pages. According to the information provided, the book originally contained 340 folios, which is equivalent to 680 pages (since each folio has two pages). However, the finished book contains 369 pages, so the number of pages that were cut can be calculated as 680 - 369 = 311 pages were cut.