The workforce is the number of people who are actively seeking work plus people who are able to work, including employees and unemployed who are actively seeking employment, so that within this group do not include mothers or children and adolescents, pensioners, students, or those workers who stopped looking for a job, regardless of the reasons for it.
In this case, we have an initial labor base of 50 million, of which all enter the labor force, even if only 20 million are employed, since it is not said that of these unemployed some amount does not seek employment.
This amount is added to the amount of people in the other group actively seeking employment, which are 10 million, because although there are another 10 million who would like a job, they are not looking for it and therefore are not part of the force labor
Answer
The labor force in that contry is b. 60 million
