1934 Guangyi Bookstore printed and published a large number of punctuated popular novels in the name of Dada Bookstore, competing with New Culture Bookstore. Although the binding of the book is simple, with kraft paper as the cover, dense fonts, no illustrations and many typos, the book sells well because of its low price, ranging from 30% to 20%, 1/2%.
There are only two possibilities in your situation. The first one is that the seller put this set of books together and put two books. Although the name is different, the content is actually not much different. Then I printed the book as it is now, changed a lot of books, and changed the name to a new book.
The second possibility is that Guangyi Bookstore bought Wenhua Bookstore, and then mixed the books printed but usable by Wenhua Bookstore with their own books. I didn't find such news, just assuming.