a. In a country, the adult population is 1200, 400 people have full-time job, 400 people work as part-time worker, while 200 people are not employed but are looking for job. Calculate the unemployment rate.

b. Three months later, the adult population is still 1200, 400 people have full-time job, 400 people work as part-time worker. Bu the economic situation in that country continuous to perform badly, and 100 people later give up hope and do not find job, while another 100 people are still looking for job. Calculate the latest unemployment rate.