According to Indian Partnership Act, 1932 the mutual rights and duties of partners in a firm can be determined by:

Section 11 of Indian Partnership Act, 1932 Subject to the provisions of this Act, the mutual rights and duties of the partners of a firm may be determined by contract between the partners, and such contract may be expressed or may be implied by a course of dealing. Such contract may be varied by consent of all the partners, and such consent may be expressed or may be implied by a course of dealing. (2) Notwithstanding anything contained in section 27 of the Indian Contract Act, 1872 (9 of 1872), such contracts may provide that a partner shall not carry on any business other than that of the firm while he is a partner.