Bunuel
At a company with 36 employees, 23 are assigned to Project Alpha, and 18 are assigned to Project Beta. How many employees are assigned to both projects?
(1) Five employees are not assigned to either project.
(2) Exactly 21 employees are assigned to only one of the two projects.
1) Alone sufficient
We are looking at a basic overlapping question.
Therefore, we look at two overlapping quantities and one underlying set, which contains all the employees.
We have:
- Non workers
- Only Alpha
- Only Beta
- Alpha and Beta
Absolute A and B are given, as well as the total.
Knowing, that there are 5 employees not assigned to any project means, that we have to distribute the 31 Workers in a way, that we have 23 on A and 18 on B. That is only possible in one way. Therefore -> Sufficient.
2) Alone sufficient
With the information of 21 Employees at only one (A OR B), we can derive to the same result as at 1), as the same logic applies here.
Therefore, the answer is D)