Vehicles begin to arrive at a toll booth at eight vehicles per minute from 9 A.M. to 10 A.M. The booth opens at 9:10 A.M. and services at a rate of 10 vehicles per minute until 9:40 A.M. From 9:40 A.M. until 10 A.M. the service rate is six vehicles per minute. Assuming D/D/1 queuing, what is the total vehicle delay from 9 A.M. to 10 A.M. assuming D/D/1 queuing?