The number of medical doctors D (in thousands) in the United States from 1998 through 2006 can be modeled by
D = 431.61 + 121.8t, 8 ¡ t ¡ 16 where t represents the year, with t = 8 corresponding to 1998.¢Ó
(a) In which year did the number of medical doctors reach 860,000?
(b) Use the model to predict in which year the number of medical doctors will reach 1,010,000.