Questions 15-16. A survey asked people how often they exceed limits. The data are categorized into the following table of counts shfwing the relationship between Age and Exceed Limit. Exceed Limit Age Always Not Always Total Under 30 100 100 200 Over 30 40 160 ' 200 Total 140 260 400 Assume that people respond to the survey independently. 15. Three people are selected randomly from age over 30, what is the probability that only one of them always exceeding the speed limit? (a) 0.128 (b) 0.256 (c) 0.384 (d) 0.512 (c) 0.640