Your questions indicate an extreme level of inexperience in business. Coupled with the fact that you don't know these people well, the likelihood of things goin

Your questions indicate an extreme level of inexperience in business. Coupled with the fact that you don't know these people well, the likelihood of things going wrong seems high. If they are offering you "25% of the business" you own 25% of the equity. As to whether that translates into an actual 25% share: maybe, maybe not. The details would be in the corporate governance document; and might include things like preferred payouts to investors, etc., which could leave you with nothing. You need to get a lawyer, or at least someone who has considerably more business knowledge, in your corner. Hint: "good contracts" are custom written, not pulled off a shelf.