8 Person Two-Facing-Rows Two-in-One Reasoning Puzzle

Eight friends of different heights stand in two rows facing each other in north-south directions. Using 9 Clues, answer 5 questions.

8 Person Two-Facing-Rows Two-in-One Reasoning Puzzle

Description

Romi, Sree, Soma, Sonia, Anju, Rupa, Devi and Meeni are eight friends all of whom have different heights. They are standing in two rows of four girls each, with four facing north and four facing south.

Clues:

1. Meeni is shorter than Romi.
2. The tallest girl among the eight is neither standing at any of the ends nor facing north.
3. Anju is shorter than Sree and is facing south.
4. Sonia is the shortest among the eight girls and is standing directly opposite Rupa who is facing south.
5. Devi is taller than Soma but shorter than Meeni.
6. Romi is standing at the second position to the right of Devi.
7. Rupa is shorter than only two girls, Anju and Sree.
8. Meeni is standing directly opposite Soma who is facing south.
9. Devi is standing at the third position to the left of Sonia.

Questions

Question 1. Who stands opposite to the tallest girl?

1. Meeni
2. Anju
3. Rupa
4. Romi
5. Devi

Question 2. Who among the following stands next to the second tallest girl?

1. Devi
2. Soma
3. Rupa
4. Anju
5. Sonia

Question 3. Which among the following five does not belong to the group formed by the other four?

1. Meeni-Romi
2. Devi-Anju
3. Sonia-Devi
4. Rupa-Romi
5. Soma-Sonia

Question 4. Which two girls are standing at the two ends of the row facing south?

1. Rupa-Sonia
2. Romi-Devi
3. Meeni-Sonia
4. Devi-Rupa
5. Rupa-Anju

Question 5. Who is standing side by side of the girl standing opposite to the second shortest girl?

1. Meeni
2. Devi
3. Rupa
4. Sonia
5. Anju

Recommended time to solve is 20 minutes.

Hints:

• Analyze the Clues in a quick scan to realize the puzzle comprises of two puzzles combined together.
• Form the critical strategy to solve the puzzle quickly based on this knowledge.

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Solution to the 8 Person Two-Facing-Rows Two-in-One Reasoning Puzzle (Bank PO): Strategic Decisions

Objectives to Answer 5 Questions:

• First objective: Eight friends are to be placed in their correct positions in the two rows facing each other.
• Second objective: Eight friends are to be ranked from the tallest to the shortest.
• A two-in-one hybrid puzzle: With two unrelated objectives, this is a puzzle with two puzzles in one.

Strategic Decisions

• Solving two intertwined puzzles together would be cumbersome and complex.
• Ranking problem involves analysis of only one parameter—"Relative height"—as "taller than", "shortest" and so on.
• With most of the clues having height ranking clues, it should be straightforward to rank the eight friends, ignoring the two rows facing each other problem altogether.
• Decisions:
• Break apart the puzzle into two puzzles.
• Solve the ranking puzzle independently first.
• Solving the two-row puzzle next should be easy with the knowledge of the eight friends already ranked by height.

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Part 1: Solution to the eight friends' height ranking puzzle

Showing Results of Ranking

• Representation of ranking will be a series of 8 names related together by ">" symbol:
• A > B means "A is taller than B".
• Transitive relations: If A > B and B > C, then a three-valued relation A > B > C forms, meaning "A is taller than B who is taller than C".
• Starting representation is the series of eight names with no ranking yet:
• Romi, Sree, Soma, Sonia, Anju, Rupa, Devi, Meeni.
• Ranking at intermediate stages: If at an intermediate stage it is discovered, "Anju is taller than Soma", the ranking series is modified to:
• Romi, Sree, Sonia, "Anju > Soma", Rupa, Devi, Meeni.
• At the end, when ranking is complete, the ranked series of friends will be of the form:
• A > B > C > D > E > F > G > H—"A" tallest, "H" shortest.

Clue Analysis for Height Ranking

Clue 1. "Meeni is shorter than Romi": Result: "Romi > Meeni".

• Ranked friends: "Romi > Meeni", Sree, Soma, Sonia, Anju, Rupa, Devi.

Clue 3. "Anju is shorter than Sree and is facing south": Result: "Sree > Anju".

• Ranked friends: "Romi > Meeni", "Sree > Anju", Soma, Sonia, Rupa, Devi.
• "facing south" is ignored as focus is on height ranking.

Clue 5. "Devi is taller than Soma but shorter than Meeni": Result: "Meeni > Devi > Soma".

• Ranked friends: "Romi > Meeni > Devi > Soma", "Sree > Anju", Sonia, Rupa.
• Logic: The ranking "Meeni > Devi > Soma" is merged with existing ranking "Romi > Meeni". As Romi is taller than Meeni, she is taller than Devi and Soma as well.

Clue 7. "Rupa is shorter than only two girls, Anju and Sree":

• Result: Rupa is third tallest, both Anju and Sree are taller than Rupa.
• Ranked: "(Anju, Sree) > Rupa".

Ranked friends: "Sree > Anju > Rupa > Romi > Meeni > Devi > Soma > Sonia".

Logic:

• With already known "Sree > Anju", the Clue 7 forms the three tallest friends ranked: "Sree > Anju > Rupa".
• Rupa being taller than the other five, the ultimate rank is automatically formed.
• Sonia happens to be the shortest by default, but is supported by Clue 4: " Sonia is the shortest among the eight girls and is standing directly opposite Rupa who is facing south."

The solution is painless and straightforward because it is solved by analyzing only the height ranking phrases in the clues.

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Part 2: Solution to the 8 Person Two Facing-Rows Positioning Reasoning Puzzle (Bank PO)

Understanding the problem

Identify the Objects:

• The objects are the eight friends: Romi, Sree, Soma, Sonia, Anju, Rupa, Devi and Meeni.
• The eight friends are differentiated into two groups: Four North-facing and Four South-facing friends forming two rows in the assignment table.

Identify the Primary object:

• Only virtual object with known values are Positions—the primary object.
• Two sets of positions:
• Top South-facing 4 positions—rightmost position 1, leftmost position 4. This forms the top header row.
• Bottom North-facing 4 positions—leftmost position 5, rightmost position 8. This forms the bottom header row.

With height ranks already known, the assignment table at the start:

Stage 1: Direct Assignments First by Logic Analysis and Link Search

Clue 4. "Sonia is the shortest among the eight girls and is standing directly opposite Rupa who is facing south."

Clue 9. "Devi is standing at the third position to the left of Sonia."

• Results: Together, the two clues confirm Rupa in position 1, Sonia in position 8 and Devi in position 5.

Further related assignment:

Clue 6. "Romi is standing at the second position to the right of Devi."

• Result: Romi in position 7.

The stage 1 assignment table:

Stage 2: Ultimate Assignments to Solution

Clue 8. "Meeni is standing directly opposite Soma who is facing south."

• Result: Meeni in position 6, the only position unoccupied in north-facing row. Soma in position 3.

Clue 2. "The tallest girl among the eight is neither standing at any of the ends nor facing north."

• Result: The tallest girl is Sree, and she stands in either position 2 or 3. With position 3 taken up Soma, Sree gets position 2.

Anju gets position 4 by default, but it is confirmed by:

Clue 3. "Anju is shorter than Sree and is facing south."

The ultimate assigned positions with heights ranked:

Answering the questions

Question 1. Who stands opposite to the tallest girl?

• Options: 1:Meeni, 2:Anju, 3:Rupa, 4:Romi, 5:Devi.

Answer 1. Option 4: Romi.

Question 2. Who among the following stands next to the second tallest girl?

• Options: 1:Devi, 2:Soma, 3:Rupa, 4:Anju, 5:Sonia.

Answer 2. Option 2: Soma.

Question 3. Which among the following five does not belong to the group formed by the other four?

• Options: 1:Meeni-Romi, 2:Devi-Anju, 3:Sonia-Devi, 4:Rupa-Romi, 5:Soma-Sonia.

Answer 3. Option 1: Meeni-Romi.

• Meeni-Romi are the only pair standing adjacent (neighbors). The other pairs are not next to each other.

Question 4. Which two girls are standing at the two ends of the row facing south?

• Options: 1:Rupa-Sonia, 2:Romi-Devi, 3:Meeni-Sonia, 4:Devi-Rupa, 5:Rupa-Anju.

Answer 4. Option 5: Rupa-Anju.

Question 5. Who is standing side by side of the girl standing opposite to the second shortest girl?

• Options: 1:Meeni, 2:Devi, 3:Rupa, 4:Sonia, 5:Anju.

Answer 5. Option 2: Devi.

• To answer this question, the last clause, "the second shortest girl" is to be processed first, and next the second last clause, "girl standing opposite (to the second shortest girl)" and lastly, the first clause last, "Standing side by side of the (girl standing opposite to the (second shortest girl))".
• First we get Soma, as the second shortest girl.
• Next we get Meeni standing opposite to Soma.
• And at the last, Devi is the only one among five who is a neighbor of Meeni. The other neighbor Romi is not in the list of five choices.

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Comments

The strategic decision—solving height ranking first—streamlined the pair of ranking and positional puzzles joined as one puzzle.

It is the critical part for solving this tricky puzzle easily.

The reasoning puzzle is from an Bank PO recruitment test. These puzzles formed an important element for screening young aspirants with quick minds and strong reasoning skills.

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