Answer
a. 10
Work Step by Step
1. 40 people who are working full time and 20 people who are working half-time are considered employed
2. 10 people who are looking for a job are a part of the labor force and are considered unemployed
3. 10 people who would like to work but are so discouraged that they have given up looking for a job are considered as discouraged workers and are not considered a part of the labor force
4. 10 full-time students and 10 retired persons are not a part of the labor force
Therefore, only 10 people are considered to be unemployed
