You need not necessarily have good qualifications in Math's to work in banks though it would be considered as an added advantage. The bank also comprises of administrative jobs which do not require knowledge of Math's. A person with average knowledge of Math's too can perform well at his job in a bank. A bank job usually requires candidates who have minimum qualifications as a Graduate in any stream. Having a previous work experience plays an important role as well. Basic knowledge of maths is expected at every job let alone jobs in banks. Even the higher level positions at the banks do not require a good qualification in maths. Your contribution to the company's growth is considered more important than the number's. In short a bank job is not related to good qualification in Math's.