Visit your local library: On a recent Saturday, a total of 1231 people visited a local library. Of these people, 253 were under age 10, 468 were aged 10-18,158 were aged 19-30, and the rest were more than 30 years old. One person is sampled at random.(a) What is the probability that the person is less than 19 years old?(b) What is the probability that the person is more than 30 years old?