Worst book for begginners, they get demotivated by seeing large formulas and irrelevant questions not even asked in mock test , it is only to be used for practice and students should try to avoid this book and purchase RS Aggarwal and Elements of Maths , and for GAT portion reffer to NCERT Books, it would be more helpful. Also if possible try to watch Arpit Choudhary sir, I can assure you that he is best teacher as per most of the students perspective and his team is good for GAT .For science you should reffer Disha published General Science
Note : this is not criticized by me, just my honest opinion and this is not a paid promotion of YouTube or any teacher.
Thank you