Timing Is Everything
medium Rich lives in the Eastern Standard Time zone. His sister, Barbara, lives in the Central European Time zone, six hours ahead of him. Rich works between 8 a.m. and 5 p.m. in his local time and goes to sleep each evening at 10 p.m. on the dot. Barbara works between 9 a.m. and 6 p.m. and always goes to sleep at 11:30 p.m. in her own local time. Is there any window in which Rich could call Barbara after his workday without interrupting her on the job or disturbing her sleep?