Your question is Predict Phone Battery Life. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Given a phone's current battery level, predict how much longer the phone can be used; implement linear interpolation in code, discuss which variables to include, and how you would predict if there is no historical data for similar phones. Asked in the onsite round 1 case study stage. The interviewer said full implementation was not needed, but the idea mattered. Be prepared to explain your variables, assumptions, interpolation method, and cold-start approach.