Hi there,
Assigning an appropriate number of hours to study for each book doesn't seem completely appropriate in terms of making sure you get the most out of our materials. Every person works at his or her own pace, so saying "you should spend three hours reading, and one hour doing the problems" doesn't seem like the best way to make sure you do well on your test!
Instead, what I can suggest for you a way to study that will hopefully include the books. When students take our 9 session course, they are assigned both verbal and quant every from our books every week, in addition to other work. However, this is a very structured approach that includes access to our other resources, such as our online labs and, of course, the classes themselves. You can see a sample syllabus of this linked from the following page, which could be helpful for you in terms of structuring your own studies, but obviously, you will want to tailor this to fit your own unique needs:
https://www.manhattangmat.com/gmat-course-gmat-book.cfmIn addition, if you are looking for help in structuring your studies, I would suggest this article:
https://www.manhattangmat.com/articles/p ... t-prep.cfm which is helpful in reminding you to analyze your strengths and weaknesses, and then focus on the weaknesses (ie spend more time on those than the stuff you already understand!) There is also a great article about using the assessment reports we provide with our CATs (which you should have access too if you purchased our books new):
https://www.manhattangmat.com/articles/a ... eports.cfmYou also will want to make sure you are really
absorbing the material. You shouldn't just do the problems in your Official Guide, for example. You should read a section of one of our books, do the In Action problems to make sure you understand the concepts, and then apply these concepts to the Official Guide problems we reference. Make sure to always set yourself a time when doing OG problems as well, since timing is very important on the GMAT.
In terms of spending 8-9 hours on Number Properties, judging by the amount of time we suggest our students study each week, that number seems reasonable enough. Just remember to spread it out, and to do both verbal and quant ever week. We suggest that studying for the GMAT should take 2-3 months, so with the pace you mentioned you should be right on target.
Let me know if you need any other help, and best of luck with your studies,
Caitlin Clay