Hello Payal.

For quantitative aptitude in bank po you can take the help of books from lucent publication.

I tell you that these books are such useful that one of my friend just completed these books thoroughly and also completed coaching and notes side by side. He got the job within one year of preparation...

So I suggest you lucent publication books and coaching notes if you are pursuing it.

All the very best.

The best books you can go through are

1-R.S Aggarwal -quantitive aptitude for competitive exams. 

2-Arun Sharma

3-Arihant publications. 

4-R. D. Sharma

5-Sarvesh. K. Verna. 

6-quicker maths is also a very good book for aptitude. 

Hope this list will help you prepare for your exam. 

All the best for any further queries feel free to ask.