In preparation for a sales interview, many candidates have asked me how many questions should they expect to be asked during a sales interview. In my research in asking other hiring sales managers as well as the average questions I usually ask when interviewing a candidate varies. It is always a good idea to prepare yourself for the most common questions and to practice your responses so that when surprise questions get asked, you have some time to think and respond, but by practicing commonly asked questions, you will have a base of answers to quickly respond with the type of answers you want to communicate to the hiring sales manager.
A lot of your answers should be customized based on the needs of the hiring sales manager and tied into what he/she is looking for. You may add support behind your core answers by linking the needs of the sales manager and your answers to provide the best answers.
On average, you can expect to be asked about 10-25 questions. Usually a good interview lasts about 60-90 minutes and it takes about 30 seconds for each question to be asked by a hiring sales manager. If you need the time to think of a response, it is OK to think before responding to ensure that you provide what you are trying to convey to the hiring sales manager.