Dear Abhijeet,
Prima facie, the offer looks like lucrative. But much would depend on what what is your operating gross margin, financial costs etc. As others said, a net profit could be arrived at only after accounting for the gross income, gross margin, operating expenses, transfer to partner's capital a/c towards investment costs and other expenses. Finally you will arrive at possible net profit/loss. Only for argument's sake, What if the business ends up in a loss finally, Does't mean that you should pay from your pocket. To be more clear just list out the Purchases cost of 'x' No.of your product being traded, for the very product what is possible sale price per unit (assuming that this product will not face any problem in selling them) and arrive at the gross sale proceeds. List out what are all your expenses like salary, Elec.bills, conveyance, handling, communication, advt. including rent if any, in cash/cheque/kind and then notionally compute, VAT & other govt.levies, cost of investment, depreciation for equipment and other assets being used for business. Now you will get a net profit before Tax (IT if applicable), then you'll get the Net profit available for sharing by partners. Here you will get a clue who is/which is going to be beneficial, an over all picture. Be frank, if it's ending with a loss you may as well continue with salary option. May be later on you might set up your own business in this line sooner once you are thorough with all aspects of this business.