Hey ezzeldin.khaled,
first of - 75 days is a fine amount of time: The optimal amount of time to study for the GMAT in general is 6-8 weeks - provided you study right.
second of all - here's a list of suggested prep material:
Download Free GMATPrep® Software -
https://www.mba.com/global/the-gmat-exam ... tware.aspx
Free GMAT Prep Flashcards -
https://www.beatthegmat.com/mba/free-gma ... flashcards
https://www.gmatfree.com
https://www.prep4gmat.com/share/?c=Free_ ... ar&pid=BTG
https://gmatclub.com/forum/all-gmatprep- ... 87679.html
https://gmatclub.com/forum/improve-your- ... 60892.html
https://www.khanacademy.org/test-prep/gmat
Third - if you've already taken the GMAT and haven't succeeded, you might want to consider taking a course. If you decide to do this, there a lot of things to consider here too. A GMAT class makes sense if you feel comfortable in a classroom setting, your budget is very high, you are self-motivated and don't have big gaps in your knowledge that need special attention, and your schedule can accommodate a course that meets at a specific time every week. However, as every GMAT student knows, the real work happens back at home, outside the classroom, when you practice and try to figure out solutions by yourself.
Nowadays, in the world of online courses, you can have a teacher-in-a-classroom experience online. On-demand classes will allow you to choose your own time and place. These are usually videos of a power point presentation showing the course material followed by a bulk of practice questions.
Live online courses are also an option. These have a similar experience to the old fashioned GMAT class except you watch the tutor through a screen. When taking an in-person or live-online course you should make sure that we will have enough face time.
A different, newer option is online computer assisted customized learning. What does this mean? Instead of reproducing the teacher-in-a-classroom experience online, a site like this uses personalized machine learning to bring the best out of each student. By monitoring thousands of other students who are tackling the same question as you, the site can provide you with the approaches that proved most efficient for each given question. examPal.com is a site such as this.
The most important thing is studying in an adaptive way - identifying your weak areas right off the bat, and more importantly - learning why you make the mistakes you do, so as to learn what and how to change. It's important to remember the GMAT itself is an adaptive exam - feeding you questions based on how you answered the previous ones. It's also crucial to understand there is usually more than one possible way to solve a question - but one way that is right (that is, fastest) for you. The trick is learning your own strengths and learning to recognize in questions which approach is best.
Here's an article with more tips on how to study -
https://exampal.com/gmat/blog/top-10-gma ... pare-gmat/
