There are seven friends A, B, C, D, E, F and G living in a seven-floor…
2026
There are seven friends A, B, C, D, E, F and G living in a seven-floor building. The ground floor is numbered 1, the floor above it is numbered 2, and so on up to floor 7.
E does not live on an even-numbered floor. G does not live on the topmost floor. Only one person lives between E and G. A does not live on an even-numbered floor and does not live below F. D does not live immediately above or immediately below G. There are two floors between D and E. Both B and C live on even-numbered floors. There are two floors between G and C. F lives on floor number 5.
Who is the immediate neighbor of G ?
- A.
B
- B.
D
- C.
E
- D.
F
Attempted by 4 students.
Show answer & explanation
Correct answer: A
Concept
In floor- or level-based seating puzzles, first fix the person(s) pinned by absolute clues (an exact floor number, an extreme position such as topmost/bottommost), then use the relative clues (fixed gaps, parity, direction) to narrow the remaining floors step by step, rejecting any partial placement that breaks a later clue, until every floor is uniquely assigned.
Application
F is fixed directly at floor 5 (an absolute clue).
A lives on an odd-numbered floor and does not live below F (floor 5); the only odd floor above 5 is floor 7, so A = 7.
With A = 7 and F = 5, floors 1, 2, 3, 4 and 6 remain for B, C, D, E and G.
E must occupy an odd floor from what remains, so E is either 1 or 3.
G is exactly two floors from E (only one person lives between them). Testing E = 1 gives G = 3; testing E = 3 gives G = 1 (G = 5 is already F's floor).
If E = 1 and G = 3, the 'two floors between D and E' clue forces D = 4 - but then D and G (floors 4 and 3) would be immediately adjacent, breaking the clue that D is not immediately above or below G. This case is rejected.
So E = 3 and G = 1. The 'two floors between D and E' clue now gives D = 6 (D = 0 is impossible), and |D - G| = 5, which satisfies the non-adjacency clue.
The two floors left, 2 and 4, go to B and C, both fixed to even-numbered floors by their own clue. The 'two floors between G and C' clue (floors 2 and 3 lying between floor 1 and floor 4) fixes C = 4, so B = 2.
Floor | Person |
|---|---|
7 | A |
6 | D |
5 | F |
4 | C |
3 | E |
2 | B |
1 | G |
Cross-check
E (floor 3) is on an odd-numbered floor.
G (floor 1) is not on the topmost floor.
Exactly one person (B, floor 2) lives between E (floor 3) and G (floor 1).
A (floor 7) is odd-numbered and does not live below F (floor 5).
D (floor 6) is not immediately above or below G (floor 1) - they are five floors apart.
Two floors (4 and 5) lie between D (floor 6) and E (floor 3).
B (floor 2) and C (floor 4) both live on even-numbered floors.
Two floors (2 and 3) lie between G (floor 1) and C (floor 4).
Every clue checks out against the layout above, so G's immediate neighbor - the person on floor 2 - is B.