Five people, L, M, N, R and S are sitting in a straight row, facing north, but not necessarily in the same order. Only M sits between L and S. N sits to the immediate right of S. R sits to the immediate left of L. Who sits at the second position from the left end?

Question

Prepp Team · Accepted Answer

Understanding the Seating Arrangement Puzzle

This problem is a classic linear seating arrangement puzzle. We are given clues about the relative positions of five people (L, M, N, R, S) sitting in a straight row, all facing north. To solve this, we need to carefully read each clue and build the arrangement step by step.

Analyzing the Clues for the Seating Arrangement

Let's break down the information provided:

There are five people: L, M, N, R, and S.
They are in a straight row, facing north. Facing north means 'right' is to our right and 'left' is to our left when looking at the arrangement.
Clue 1: Only M sits between L and S. This tells us that L, M, and S are together in that specific order (L-M-S) or the reverse order (S-M-L). No other person is between L and S.
Clue 2: N sits to the immediate right of S. This means N is directly next to S on S's right side. If S is somewhere, N is immediately after S.
Clue 3: R sits to the immediate left of L. This means R is directly next to L on L's left side. If L is somewhere, R is immediately before L.

Deducing the Final Seating Order

Let's use the clues to figure out the complete arrangement of the five people. From Clue 1, we know the block L-M-S or S-M-L exists.

Consider the first possibility from Clue 1: L-M-S.

If we have L-M-S, let's apply Clue 2 (N is immediate right of S). Adding N to the right of S gives us the sequence L-M-S-N.
Now let's apply Clue 3 (R is immediate left of L). Adding R to the left of L in the sequence L-M-S-N gives us R-L-M-S-N.
This arrangement R-L-M-S-N includes all five people (R, L, M, S, N) and fits all the clues:
- Only M is between L and S (Yes, L-M-S is present).
- N is to the immediate right of S (Yes, S-N is present).
- R is to the immediate left of L (Yes, R-L is present).

Consider the second possibility from Clue 1: S-M-L.

If we have S-M-L, let's apply Clue 2 (N is immediate right of S). Adding N to the right of S gives us N-S-M-L (N is to the immediate right of S when facing north, so S is to the immediate left of N). This contradicts Clue 2 which says N is to the immediate right of S. Let's be more precise: If the sequence is S-M-L, and they face North, the order from left to right is S then M then L. N immediately right of S means the sequence starts S-N. This contradicts the S-M-L block starting with S.
Let's re-evaluate S-M-L with N immediate right of S. This would be S-N and then followed by M-L somewhere after M. This doesn't fit the "Only M sits between L and S" part if the block is S-M-L as a unit.
Alternatively, if the block S-M-L is part of the arrangement, and N is immediately right of S, the sequence locally looks like S-N.... The S-M-L block cannot start with S if N is immediately right of S, as N must be to the right. If the block is S-M-L, then N cannot be immediately right of S within this block or immediately after it in a way that keeps L and S with only M between them.

Let's stick to the first possibility which worked perfectly. The confirmed arrangement from left to right is:

R - L - M - S - N

Finding the Second Position from the Left

The question asks who sits at the second position from the left end. Looking at our arrangement R-L-M-S-N:

The first position from the left is R.
The second position from the left is L.
The third position from the left is M.
The fourth position from the left is S.
The fifth position from the left is N.

Therefore, the person sitting at the second position from the left end is L.

Position (from Left)	Person
1st	R
2nd	L
3rd	M
4th	S
5th	N

Revision Table: Seating Arrangement Facts

Clue Summary	Deduction / Result
5 people: L, M, N, R, S	Total number of positions is 5.
Facing North	Left is to the left, Right is to the right.
Only M sits between L and S	Forms a block: L-M-S or S-M-L.
N sits immediate right of S	S is immediately followed by N. Sequence S-N.
R sits immediate left of L	R is immediately before L. Sequence R-L.
Combined Deductions	The arrangement must be R-L-M-S-N.
Second position from left	The person at the 2nd spot is L.

Additional Information: Tips for Seating Arrangement Questions

Seating arrangement questions are common in logical reasoning. Here are some tips to help you solve them:

Read Carefully: Pay close attention to keywords like "immediate left," "immediate right," "to the left," "to the right," "between," "at one end," etc.
Draw a Diagram: For linear arrangements, drawing a straight line with slots helps visualize the positions. For circular arrangements, draw a circle.
Use Direct Clues First: Start with clues that give you a fixed position or a fixed block of people.
Combine Clues: Look for ways to link different clues together. For example, if A is next to B, and B is next to C, you might have A-B-C or C-B-A.
Check Possibilities: If a clue offers multiple possibilities (like L-M-S or S-M-L), explore each one and see which one fits all the other clues. Eliminate possibilities that lead to contradictions.
Account for All Individuals: Make sure your final arrangement includes everyone mentioned in the question.
Verify the Final Arrangement: Once you have an arrangement, re-read all the original clues and check if your arrangement satisfies every single condition.
Answer the Specific Question: After finding the arrangement, make sure you answer exactly what the question asks (e.g., who is at a certain position, how many people are between X and Y).