It is given that,
Seven persons A, B, C, D, E, F and G live in a building consisting of seven floors, but not necessarily in the same order.
The floors are numbered as 1 to 7 from bottommost to topmost floor.
D lives immediately below F.
From statement I alone:
Four persons live between B and E, who lives on an even numbered floor below B and G.
Three persons live between A and G.
| Floors | Persons |
| 7 | B |
| 6 | |
| 5 | G |
| 4 | |
| 3 | |
| 2 | E |
| 1 | A |
D lives immediately below F.
| Floors | Persons |
| 7 | B |
| 6 | |
| 5 | G |
| 4 | F |
| 3 | D |
| 2 | E |
| 1 | A |
So, finally we get:
| Floors | Persons |
| 7 | B |
| 6 | C |
| 5 | G |
| 4 | F |
| 3 | D |
| 2 | E |
| 1 | A |
Therefore, F lives exactly on the middle floor of a building.
So, statement I alone is sufficient to answer the question.
From statement II alone:
D lives immediately below F.
| | Case 1 | Case 2 | Case 3 | Case 4 | Case 5 | Case 6 |
| Floors | Persons | Persons | Persons | Persons | Persons | Persons |
| 7 | F | | | | | |
| 6 | D | F | | | | |
| 5 | | D | F | | | |
| 4 | | | D | F | | |
| 3 | | | | D | F | |
| 2 | | | | | D | F |
| 1 | | | | | | D |
G lives immediately below C but not below A.
Two persons live between A and D.
| | Case 1 | Case 2 | Case 3 | Case 3a | Case 5 | Case 6 | Case 6a |
| Floors | Persons | Persons | Persons | Persons | Persons | Persons | Persons |
| 7 | F | | C | | C | C | |
| 6 | D | F | G | | G | G | C |
| 5 | C | D | F | F | A | | G |
| 4 | G | C | D | D | | A | A |
| 3 | A | G | | C | F | | |
| 2 | | A | | G | D | F | F |
| 1 | | | A | A | | D | D |
B lives on an odd numbered floor.
| | Case 1 | Case 2 | Case 3 | Case 3a | Case 5 | Case 6 | Case 6a |
| Floors | Persons | Persons | Persons | Persons | Persons | Persons | Persons |
| 7 | F | B/E | C | B | C | C | B/E |
| 6 | D | F | G | E | G | G | C |
| 5 | C | D | F | F | A | B/E | G |
| 4 | G | C | D | D | E | A | A |
| 3 | A | G | B | C | F | B/E | B/E |
| 2 | E | A | E | G | D | F | F |
| 1 | B | B/E | A | A | B | D | D |
Thus, no definite answer can be concluded.
So, statement II alone is not sufficient.
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