Researchers at Kurume University in Japan surveyed 225 workers aged 41 to 60 years and found that 30% of them were skilled workers and 70% were unskilled. At the time of survey, 15% of skilled workers and 30% of unskilled workers were on an assembly line. A worker is selected at random from the age group 41 to 60.
a. What is the probability that the worker is on an assembly line?
b. Given that the worker is on an assembly line, what is the probability that the worker is unskilled?