Gastro esophageal Reflux Disease (GERD) is a condition in which the liquid content of the stomach backs up into the esophagus. Every year, an average of 800,000 adults are diagnosed with GERD in the US. (a) [2] Suppose the estimated residual life expectancy across all US patients once diagnosed with GERD is 55 years (the residual life expectancy is the expected number of remaining years of life). What is the average number of patients in the US diagnosed with GERD at any given time? (b) [2] About 25% of the patients diagnosed yearly with GERD develop Barrett’s Esophagus after their initial GERD diagnosis. Barrett’s esophagus does not cause symptoms itself and is important only because it seems to precede the development of esophageal cancer. According to some estimates, the average number of patients in the US with Barrett’s Esophagus previously diagnosed with GERD is 4 million. What is the residual life expectancy (in years) of GERD patients who develop Barrett’s Esophagus?