1. The question asks us to
assess the scenarios and decide which pair can jointly coexist.
2. Some first observations/restrictions are: Legal, Administrative, Human Resources have to be on the 1st or 2nd floors, Finance, Marketing have to be on the 2nd or 3rd floors, and the 1st/3rd floors cannot have 3 or more departments.
3. Now let's look at each case separately:
-
The Finance and Information Technology departments only. If this were to be true, then these departments would have to be on the third floor. So, Legal and Administrative are on the second floor. In addition, Marketing would have to be on the second floor and Human Resources on the first.
| 1 | 2 | 3 |
| Finance | | | o |
| Information Technology | | | o |
| Legal | | o | |
| Administrative | | o | |
| Marketing | | o | |
| Human Resources | o | | |
-
The Finance and Marketing departments only. These can't be on the first floor and so must be on the third. Then, Legal, Administrative, and Human Resources are all on the second floor. Finally, Information Technology is left for the first floor.
| 1 | 2 | 3 |
| Finance | | | o |
| Information Technology | o | | |
| Legal | | o | |
| Administrative | | o | |
| Marketing | | | o |
| Human Resources | | o | |
-
The Legal and Administrative departments only. These have to be on the first floor, and as a result, Finance is on the second floor. Human Resources can only go on the second floor with Marketing on the third. That leaves Information Technology on the second floor.
| 1 | 2 | 3 |
| Finance | | o | |
| Information Technology | | o | |
| Legal | o | | |
| Administrative | o | | |
| Marketing | | | o |
| Human Resources | | o | |
-
The Human Resources Department only. This has to go on the first floor, and as a result, Marketing is on the second floor. Legal and Administrative both can't go on the first, so they must both go on the second floor with Finance on the third. Finally, Information Technology is on the third floor.
| 1 | 2 | 3 |
| Finance | | | o |
| Information Technology | | | o |
| Legal | | o | |
| Administrative | | o | |
| Marketing | | o | |
| Human Resources | o | | |
-
The Legal, Administrative, and Marketing departments only. All three can only coexist on the second floor, however, only the first and third floors are given as options. So, this is impossible.
4. In conclusion, the 1st and 4th cases give us exactly the same end scenarios, which means both can coexist.
5. Our answer will be:
First floor - The Finance and Information Technology departments only and Third floor - The Human Resources Department only.