What probability model should you use? (Specify the parameters as well.)

The U.S. Census Bureau’s 2007 Survey of Business Owners showed that 28.7% of all non-farm businesses are owned by women. You are phoning local businesses and assume that the national percentage is true in your area. You wonder how many calls you will have to make before you find one owned by a woman. What probability model should you use? (Specify the parameters as well.)