Vehicles begin to arrive at a parking lot at 6:00am at a rate of eight per minute. Due to an accident of the access road, no vehicles arrive from 6:20am to 6:30am. From 6:30am on, vehicles arrive at a rate of two per minute. The parking lot opens at 6:00am, and the attendant processes incoming vehicles (collects parking fees etc.) at a rate of four vehicles per minute. Assuming D/D/1 queuing, answer the following questions. 1. When does the queue clear