i ran the job interview as a recruiter i was interviewing a data engineer one of the question i asked is - if i'm a bank and want to set up ATMs in a new city how do i plan the number of ATMs ? the main purpose is to see the person logics , if he start to draw equations he is gone too far.. the question can be - an ATM serve 1000 people per day per area and the city has 200K pop so the estimated ATMs would be ~200