Dear Shruthi , In gate , aptitude section is having weightage of 15 marks(10 for reasoning and 5 for english). These are considered as bonus marks. But many people take it lightly or leave it for last minute.

So these are the books which are best for your gate preparation

1. For gate aptitude :-

(a) RS Agarwaal

Old is gold. This book is more than sufficient. Infact, for most of the aptitude tests , this book can be referred.

(b) Made easy publications

Add on material

2. For gate mathematics previous year questions solved with answers

Arihant's chapterwise solved paper mathematics gate 2020

It contains all the previous year questions solved chapterwise which enhances and organizes your preparation.

So work hard. Best of luck!!