Books like Secrets of the Nile
Carolyn Keene
Secrets of the Nile is 216 pages, about 3 hours 58 minutes at 250 words a minute.
10 books to read next
How long each takes
A Matter of Choice 4.7 h 
High Stakes 4.1 h 
The Hardy Boys and Nancy Drew Meet Dracula 2.9 h 
Nancy Drew, Girl Detective 1.8 h 
Judy Moody, Girl Detective 3.4 h 
Mad House 1.8 h 
The Phantom of Nantucket 3.5 h 
The Ocean of Osyria 1.8 h 
The Deadliest Stunt 2.1 h 
Global Warning 2.1 h Bar height shows length. Estimated at 250 words a minute.