IBPS PO mains quantitative aptitude question & answer/ want to answer aptitude test

 You need two books.

A book where you can learn in detail and practice. One such book is by R. S. Agrawal.

Another book where you can see last year's Q&A. In this case I would say Arihant's book. The book( Name- 20 years Bank PO Quantitative Aptitude)  containsq and answers from the past 20 years 

OR

another book (Name- IBPS PO 9 year preliminary & main) is also important.

You can also download the PDF by searching on Google.

Ask questions to learn more.