We start with simple questions, and can make out in 5 min whether to go forward with harder ones. We have many types of jobs, starting from very routine ones to very complex mathematical, signal processing based core work. Depending on where the candidate fits in, we may offer internship/job even for the people who do not show exemplary skills. Often people want to be assigned 'glamorous' tasks so that they can write it on their cv, even though they may not possess the necessary skills for it. We cannot afford to assign tasks like that. And that is where the conflict comes in.