Hi Aspirant,

For preparation of Bank PO examination you can refer Quantitative Aptitude book by RS Aggarwal, Bank PO quantitative aptitude by Arun Sharma and can also use Quantam CAT by Servesh Verma of Arihant Publication(Best for bank PO upto level1). The books referred now are some of the best recommended books by those who were once a Bank PO aspirant and now is serving as Bank PO.

Hope this helps.

Good luck!!