Directions: Study the following information to answer the given Questions: Eight persons Dhruv, Dipak, Khush, Sapna, Sudhir, Vaibhav, Vimal and Vivek lives on eight different floors of 8-storey building from bottom to top such as ground floor is numbered as 1st and top floor is numbered as 8th.Vaibhav lives on even numbered floor but not on 6th floor. Vivek lives below Khush’s floor. Sudhir lives two floors above Dipak’s floor. Dhruv lives on an even numbered floor but not adjacent to Sudhir’s floor. Vaibhav lives just above Vimal’s floor. Khush lives on 3rd floor. Sudhir does not live on topmost floor. Sapna’s floor is not adjacent to Dipak’s floor. How many persons live between Vaibhav’s and Dipak’s floor?
- (a)Three
- (b)Five
- (c)Four
- (d)Six
Answer
Why
Correct — B.
Rule: fix the stated floors first, then let each condition knock out cases.
Khush is on 3, so Vivek, below him, is on 1 or 2.
Vaibhav (2, 4 or 8) has Vimal just below. On 2, Vivek has no floor left; on 4, Vimal lands on Khush's 3. So Vaibhav 8, Vimal 7.
Sudhir = Dipak + 2 gives Dipak 2, Sudhir 4 or Dipak 4, Sudhir 6.
With Dipak on 4, floors 1, 2 and 5 are left. Dhruv needs an even floor, so he takes 2, Vivek 1 and Sapna 5, next to Dipak. That case fails.
With Dipak on 2: Vivek 1, Sapna 5, Dhruv 6 (even, not next to Sudhir).
Order from floor 1: Vivek, Dipak, Khush, Sudhir, Sapna, Dhruv, Vimal, Vaibhav.
Floors 3 to 7 lie between Dipak (2) and Vaibhav (8): five persons → option (b).
Why the others are wrong
- (a)Three — Three is what the rejected case gives: Dipak on 4 leaves floors 5, 6 and 7 below Vaibhav. That case fails because Dhruv, needing an even floor, takes 2 and pushes Sapna to 5, next to Dipak.
- (c)Four — Four drops a floor from the count. Floors 3, 4, 5, 6 and 7 all lie strictly between Dipak on 2 and Vaibhav on 8, and each holds one person.
- (d)Six — Six is the floor difference, 8 − 2. The persons strictly between are one fewer: 8 − 2 − 1 = 5.
Concept
A floor puzzle is a one-line ordering: eight people, eight numbered slots. Start from the absolute clue (Khush on 3), then the tight relative ones (Vaibhav just above Vimal, Sudhir two above Dipak), and branch only where a clue leaves two choices.
Test each branch against the leftover conditions. Here Dhruv's even floor and Sapna not next to Dipak kill the second branch together.
'How many between' counts the floors strictly inside the two ends: difference − 1.
Neither clue rejects the second branch alone.
Without Dhruv's clue, Dhruv can take 5, with Vivek and Sapna on 1 and 2, clear of Dipak on 4.
Without Sapna's clue, Dhruv 2, Vivek 1 and Sapna 5 stands.
Either order fits every other clue and gives three. With both clues, Dhruv is kept off 5 (odd, and next to Sudhir on 6), and Sapna, left on 5, sits next to Dipak.
Key facts
- Final order from floor 1 to floor 8: Vivek, Dipak, Khush, Sudhir, Sapna, Dhruv, Vimal, Vaibhav.
- Persons strictly between floors a and b (a below b) = b − a − 1.
- Vaibhav must be on 8: floor 2 leaves Vivek no room below Khush, and floor 4 puts Vimal on Khush's floor.
Study next
Common traps
- Answering the floor difference (6) instead of the persons strictly between (5).
- Stopping at the first order that fits the early clues without testing Sapna's 'not adjacent' clue.
- Skipping Dhruv's clue (even floor, not next to Sudhir) in the Dipak-on-4 case: Dhruv can then take 5, every other clue fits, and the count comes out three.
The identical eight-person set-up appears at 20 Sep 2025, 12:30, Reasoning Q.14, which asks who lives two floors below Sapna: Khush, on 3, from the same order.
Related PYQs
No directly related past PYQ was found.