Typically, on receiving the case and asking the clarifying questions, the protocol is to ask for some time to come up with your structure / hypothesis before you explain your approach to solve the case to the interviewer.
What is the right amount of time that would be considered acceptable to the interviewer? Is 3-4 minutes too long? Or acceptable? I timed myself for one of the cases and 1 minute is too short. I may be able to get by in 2 minutes but that is on a standard case. On an unconventional case, the thought process is longer.
Thanks for answering!