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Linear Single Row South Facing: Worksheet 6 - Intermediate-Advanced Practice Linear Single Row South Facing INTERMEDIATE ADVANCED

Ready to master Linear Single Row South Facing? This timed practice ⚡ worksheet (6/10) presents 20 intermediate-advanced-level challenges. Focus area: speed building. Learn to solve linear single row south facing tricks, handle linear single row south facing shortcut methods, and perfect linear single row south facing bank exam questions with our step-by-step solutions.

📝 Worksheet 6 of 10 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Intermediate Advanced level

What you'll learn in this worksheet:
Your progress through Linear Single Row South Facing
Worksheet 6 of 10 (55% complete)

Question 1

Five friends R, S, P, Q and T are sitting in a row facing South. R sits at the right extreme end. S sits second to the right of P. T sits immediately to the right of P (from viewer's perspective). Q is not adjacent to R. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- R at the right extreme end → Position 5
- S sits second to the right of P:
South-facing right = viewer's left = lower position: pos[S] = pos[P] - 2
Possible: P=3→S=1, or P=4→S=2
- T sits immediately to the right of P (viewer's right = higher pos): pos[T] = pos[P] + 1
If P=3 → T=4 ✓ (pos 4 free)
If P=4 → T=5 = R ✗ (conflict)
∴ P=3, S=1, T=4

Position: S _ P T R

Step 4: Apply constraint
- Q not adjacent to R (pos 5): Q ≠ pos 4 (taken by T) → Q at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S Q P T R

Verification:
✓ R at right extreme end (pos 5)
✓ S second to right of P: pos[S](=1)-2 = 3 = pos[P] (south-facing right=lower)
✓ T immediately right of P (viewer right): pos 3+1 = 4
✓ Q not adjacent to R (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 2

Five friends Q, R, S, P and T are sitting in a row facing South. Q sits at the right extreme end. R sits second to the right of S. T sits immediately to the right of S (from viewer's perspective). P is not adjacent to Q. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- Q at the right extreme end → Position 5
- R sits second to the right of S:
South-facing right = viewer's left = lower position: pos[R] = pos[S] - 2
Possible: S=3→R=1, or S=4→R=2
- T sits immediately to the right of S (viewer's right = higher pos): pos[T] = pos[S] + 1
If S=3 → T=4 ✓ (pos 4 free)
If S=4 → T=5 = Q ✗ (conflict)
∴ S=3, R=1, T=4

Position: R _ S T Q

Step 4: Apply constraint
- P not adjacent to Q (pos 5): P ≠ pos 4 (taken by T) → P at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: R P S T Q

Verification:
✓ Q at right extreme end (pos 5)
✓ R second to right of S: pos[R](=1)-2 = 3 = pos[S] (south-facing right=lower)
✓ T immediately right of S (viewer right): pos 3+1 = 4
✓ P not adjacent to Q (pos 2, not pos 4)

Answer: R sits at the left extreme end (position 1).

Question 3

Five friends S, P, Q, T and R are sitting in a row facing South. S sits at the right extreme end. P sits second to the right of Q. R sits immediately to the right of Q (from viewer's perspective). T is not adjacent to S. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- S at the right extreme end → Position 5
- P sits second to the right of Q:
South-facing right = viewer's left = lower position: pos[P] = pos[Q] - 2
Possible: Q=3→P=1, or Q=4→P=2
- R sits immediately to the right of Q (viewer's right = higher pos): pos[R] = pos[Q] + 1
If Q=3 → R=4 ✓ (pos 4 free)
If Q=4 → R=5 = S ✗ (conflict)
∴ Q=3, P=1, R=4

Position: P _ Q R S

Step 4: Apply constraint
- T not adjacent to S (pos 5): T ≠ pos 4 (taken by R) → T at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: P T Q R S

Verification:
✓ S at right extreme end (pos 5)
✓ P second to right of Q: pos[P](=1)-2 = 3 = pos[Q] (south-facing right=lower)
✓ R immediately right of Q (viewer right): pos 3+1 = 4
✓ T not adjacent to S (pos 2, not pos 4)

Answer: P sits at the left extreme end (position 1).

Question 4

Five friends Q, R, S, P and T are sitting in a row facing South. Q sits at the right extreme end. R sits second to the right of S. T sits immediately to the right of S (from viewer's perspective). P is not adjacent to Q. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- Q at the right extreme end → Position 5
- R sits second to the right of S:
South-facing right = viewer's left = lower position: pos[R] = pos[S] - 2
Possible: S=3→R=1, or S=4→R=2
- T sits immediately to the right of S (viewer's right = higher pos): pos[T] = pos[S] + 1
If S=3 → T=4 ✓ (pos 4 free)
If S=4 → T=5 = Q ✗ (conflict)
∴ S=3, R=1, T=4

Position: R _ S T Q

Step 4: Apply constraint
- P not adjacent to Q (pos 5): P ≠ pos 4 (taken by T) → P at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: R P S T Q

Verification:
✓ Q at right extreme end (pos 5)
✓ R second to right of S: pos[R](=1)-2 = 3 = pos[S] (south-facing right=lower)
✓ T immediately right of S (viewer right): pos 3+1 = 4
✓ P not adjacent to Q (pos 2, not pos 4)

Answer: R sits at the left extreme end (position 1).

Question 5

Five friends R, Q, T, S and P are sitting in a row facing South. R sits at the right extreme end. Q sits second to the right of T. P sits immediately to the right of T (from viewer's perspective). S is not adjacent to R. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- R at the right extreme end → Position 5
- Q sits second to the right of T:
South-facing right = viewer's left = lower position: pos[Q] = pos[T] - 2
Possible: T=3→Q=1, or T=4→Q=2
- P sits immediately to the right of T (viewer's right = higher pos): pos[P] = pos[T] + 1
If T=3 → P=4 ✓ (pos 4 free)
If T=4 → P=5 = R ✗ (conflict)
∴ T=3, Q=1, P=4

Position: Q _ T P R

Step 4: Apply constraint
- S not adjacent to R (pos 5): S ≠ pos 4 (taken by P) → S at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: Q S T P R

Verification:
✓ R at right extreme end (pos 5)
✓ Q second to right of T: pos[Q](=1)-2 = 3 = pos[T] (south-facing right=lower)
✓ P immediately right of T (viewer right): pos 3+1 = 4
✓ S not adjacent to R (pos 2, not pos 4)

Answer: Q sits at the left extreme end (position 1).

Question 6

Five friends Q, S, R, P and T are sitting in a row facing South. Q sits at the right extreme end. S sits second to the right of R. T sits immediately to the right of R (from viewer's perspective). P is not adjacent to Q. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- Q at the right extreme end → Position 5
- S sits second to the right of R:
South-facing right = viewer's left = lower position: pos[S] = pos[R] - 2
Possible: R=3→S=1, or R=4→S=2
- T sits immediately to the right of R (viewer's right = higher pos): pos[T] = pos[R] + 1
If R=3 → T=4 ✓ (pos 4 free)
If R=4 → T=5 = Q ✗ (conflict)
∴ R=3, S=1, T=4

Position: S _ R T Q

Step 4: Apply constraint
- P not adjacent to Q (pos 5): P ≠ pos 4 (taken by T) → P at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S P R T Q

Verification:
✓ Q at right extreme end (pos 5)
✓ S second to right of R: pos[S](=1)-2 = 3 = pos[R] (south-facing right=lower)
✓ T immediately right of R (viewer right): pos 3+1 = 4
✓ P not adjacent to Q (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 7

Five friends P, T, S, Q and R are sitting in a row facing South. P sits at the right extreme end. T sits second to the right of S. R sits immediately to the right of S (from viewer's perspective). Q is not adjacent to P. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- P at the right extreme end → Position 5
- T sits second to the right of S:
South-facing right = viewer's left = lower position: pos[T] = pos[S] - 2
Possible: S=3→T=1, or S=4→T=2
- R sits immediately to the right of S (viewer's right = higher pos): pos[R] = pos[S] + 1
If S=3 → R=4 ✓ (pos 4 free)
If S=4 → R=5 = P ✗ (conflict)
∴ S=3, T=1, R=4

Position: T _ S R P

Step 4: Apply constraint
- Q not adjacent to P (pos 5): Q ≠ pos 4 (taken by R) → Q at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: T Q S R P

Verification:
✓ P at right extreme end (pos 5)
✓ T second to right of S: pos[T](=1)-2 = 3 = pos[S] (south-facing right=lower)
✓ R immediately right of S (viewer right): pos 3+1 = 4
✓ Q not adjacent to P (pos 2, not pos 4)

Answer: T sits at the left extreme end (position 1).

Question 8

Five friends S, Q, R, T and P are sitting in a row facing South. S sits at the right extreme end. Q sits second to the right of R. P sits immediately to the right of R (from viewer's perspective). T is not adjacent to S. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- S at the right extreme end → Position 5
- Q sits second to the right of R:
South-facing right = viewer's left = lower position: pos[Q] = pos[R] - 2
Possible: R=3→Q=1, or R=4→Q=2
- P sits immediately to the right of R (viewer's right = higher pos): pos[P] = pos[R] + 1
If R=3 → P=4 ✓ (pos 4 free)
If R=4 → P=5 = S ✗ (conflict)
∴ R=3, Q=1, P=4

Position: Q _ R P S

Step 4: Apply constraint
- T not adjacent to S (pos 5): T ≠ pos 4 (taken by P) → T at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: Q T R P S

Verification:
✓ S at right extreme end (pos 5)
✓ Q second to right of R: pos[Q](=1)-2 = 3 = pos[R] (south-facing right=lower)
✓ P immediately right of R (viewer right): pos 3+1 = 4
✓ T not adjacent to S (pos 2, not pos 4)

Answer: Q sits at the left extreme end (position 1).

Question 9

Five friends Q, T, P, S and R are sitting in a row facing South. Q sits at the right extreme end. T sits second to the right of P. R sits immediately to the right of P (from viewer's perspective). S is not adjacent to Q. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- Q at the right extreme end → Position 5
- T sits second to the right of P:
South-facing right = viewer's left = lower position: pos[T] = pos[P] - 2
Possible: P=3→T=1, or P=4→T=2
- R sits immediately to the right of P (viewer's right = higher pos): pos[R] = pos[P] + 1
If P=3 → R=4 ✓ (pos 4 free)
If P=4 → R=5 = Q ✗ (conflict)
∴ P=3, T=1, R=4

Position: T _ P R Q

Step 4: Apply constraint
- S not adjacent to Q (pos 5): S ≠ pos 4 (taken by R) → S at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: T S P R Q

Verification:
✓ Q at right extreme end (pos 5)
✓ T second to right of P: pos[T](=1)-2 = 3 = pos[P] (south-facing right=lower)
✓ R immediately right of P (viewer right): pos 3+1 = 4
✓ S not adjacent to Q (pos 2, not pos 4)

Answer: T sits at the left extreme end (position 1).

Question 10

Five friends T, S, R, Q and P are sitting in a row facing South. T sits at the right extreme end. S sits second to the right of R. P sits immediately to the right of R (from viewer's perspective). Q is not adjacent to T. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- T at the right extreme end → Position 5
- S sits second to the right of R:
South-facing right = viewer's left = lower position: pos[S] = pos[R] - 2
Possible: R=3→S=1, or R=4→S=2
- P sits immediately to the right of R (viewer's right = higher pos): pos[P] = pos[R] + 1
If R=3 → P=4 ✓ (pos 4 free)
If R=4 → P=5 = T ✗ (conflict)
∴ R=3, S=1, P=4

Position: S _ R P T

Step 4: Apply constraint
- Q not adjacent to T (pos 5): Q ≠ pos 4 (taken by P) → Q at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S Q R P T

Verification:
✓ T at right extreme end (pos 5)
✓ S second to right of R: pos[S](=1)-2 = 3 = pos[R] (south-facing right=lower)
✓ P immediately right of R (viewer right): pos 3+1 = 4
✓ Q not adjacent to T (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 11

Five friends Q, S, T, R and P are sitting in a row facing South. Q sits at the right extreme end. S sits second to the right of T. P sits immediately to the right of T (from viewer's perspective). R is not adjacent to Q. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- Q at the right extreme end → Position 5
- S sits second to the right of T:
South-facing right = viewer's left = lower position: pos[S] = pos[T] - 2
Possible: T=3→S=1, or T=4→S=2
- P sits immediately to the right of T (viewer's right = higher pos): pos[P] = pos[T] + 1
If T=3 → P=4 ✓ (pos 4 free)
If T=4 → P=5 = Q ✗ (conflict)
∴ T=3, S=1, P=4

Position: S _ T P Q

Step 4: Apply constraint
- R not adjacent to Q (pos 5): R ≠ pos 4 (taken by P) → R at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S R T P Q

Verification:
✓ Q at right extreme end (pos 5)
✓ S second to right of T: pos[S](=1)-2 = 3 = pos[T] (south-facing right=lower)
✓ P immediately right of T (viewer right): pos 3+1 = 4
✓ R not adjacent to Q (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 12

Five friends T, Q, S, P and R are sitting in a row facing South. T sits at the right extreme end. Q sits second to the right of S. R sits immediately to the right of S (from viewer's perspective). P is not adjacent to T. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- T at the right extreme end → Position 5
- Q sits second to the right of S:
South-facing right = viewer's left = lower position: pos[Q] = pos[S] - 2
Possible: S=3→Q=1, or S=4→Q=2
- R sits immediately to the right of S (viewer's right = higher pos): pos[R] = pos[S] + 1
If S=3 → R=4 ✓ (pos 4 free)
If S=4 → R=5 = T ✗ (conflict)
∴ S=3, Q=1, R=4

Position: Q _ S R T

Step 4: Apply constraint
- P not adjacent to T (pos 5): P ≠ pos 4 (taken by R) → P at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: Q P S R T

Verification:
✓ T at right extreme end (pos 5)
✓ Q second to right of S: pos[Q](=1)-2 = 3 = pos[S] (south-facing right=lower)
✓ R immediately right of S (viewer right): pos 3+1 = 4
✓ P not adjacent to T (pos 2, not pos 4)

Answer: Q sits at the left extreme end (position 1).

Question 13

Five friends R, S, T, P and Q are sitting in a row facing South. R sits at the right extreme end. S sits second to the right of T. Q sits immediately to the right of T (from viewer's perspective). P is not adjacent to R. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- R at the right extreme end → Position 5
- S sits second to the right of T:
South-facing right = viewer's left = lower position: pos[S] = pos[T] - 2
Possible: T=3→S=1, or T=4→S=2
- Q sits immediately to the right of T (viewer's right = higher pos): pos[Q] = pos[T] + 1
If T=3 → Q=4 ✓ (pos 4 free)
If T=4 → Q=5 = R ✗ (conflict)
∴ T=3, S=1, Q=4

Position: S _ T Q R

Step 4: Apply constraint
- P not adjacent to R (pos 5): P ≠ pos 4 (taken by Q) → P at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S P T Q R

Verification:
✓ R at right extreme end (pos 5)
✓ S second to right of T: pos[S](=1)-2 = 3 = pos[T] (south-facing right=lower)
✓ Q immediately right of T (viewer right): pos 3+1 = 4
✓ P not adjacent to R (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 14

Five friends S, R, T, Q and P are sitting in a row facing South. S sits at the right extreme end. R sits second to the right of T. P sits immediately to the right of T (from viewer's perspective). Q is not adjacent to S. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- S at the right extreme end → Position 5
- R sits second to the right of T:
South-facing right = viewer's left = lower position: pos[R] = pos[T] - 2
Possible: T=3→R=1, or T=4→R=2
- P sits immediately to the right of T (viewer's right = higher pos): pos[P] = pos[T] + 1
If T=3 → P=4 ✓ (pos 4 free)
If T=4 → P=5 = S ✗ (conflict)
∴ T=3, R=1, P=4

Position: R _ T P S

Step 4: Apply constraint
- Q not adjacent to S (pos 5): Q ≠ pos 4 (taken by P) → Q at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: R Q T P S

Verification:
✓ S at right extreme end (pos 5)
✓ R second to right of T: pos[R](=1)-2 = 3 = pos[T] (south-facing right=lower)
✓ P immediately right of T (viewer right): pos 3+1 = 4
✓ Q not adjacent to S (pos 2, not pos 4)

Answer: R sits at the left extreme end (position 1).

Question 15

Five friends S, R, P, T and Q are sitting in a row facing South. S sits at the right extreme end. R sits second to the right of P. Q sits immediately to the right of P (from viewer's perspective). T is not adjacent to S. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- S at the right extreme end → Position 5
- R sits second to the right of P:
South-facing right = viewer's left = lower position: pos[R] = pos[P] - 2
Possible: P=3→R=1, or P=4→R=2
- Q sits immediately to the right of P (viewer's right = higher pos): pos[Q] = pos[P] + 1
If P=3 → Q=4 ✓ (pos 4 free)
If P=4 → Q=5 = S ✗ (conflict)
∴ P=3, R=1, Q=4

Position: R _ P Q S

Step 4: Apply constraint
- T not adjacent to S (pos 5): T ≠ pos 4 (taken by Q) → T at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: R T P Q S

Verification:
✓ S at right extreme end (pos 5)
✓ R second to right of P: pos[R](=1)-2 = 3 = pos[P] (south-facing right=lower)
✓ Q immediately right of P (viewer right): pos 3+1 = 4
✓ T not adjacent to S (pos 2, not pos 4)

Answer: R sits at the left extreme end (position 1).

Question 16

Five friends R, P, Q, S and T are sitting in a row facing South. R sits at the right extreme end. P sits second to the right of Q. T sits immediately to the right of Q (from viewer's perspective). S is not adjacent to R. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- R at the right extreme end → Position 5
- P sits second to the right of Q:
South-facing right = viewer's left = lower position: pos[P] = pos[Q] - 2
Possible: Q=3→P=1, or Q=4→P=2
- T sits immediately to the right of Q (viewer's right = higher pos): pos[T] = pos[Q] + 1
If Q=3 → T=4 ✓ (pos 4 free)
If Q=4 → T=5 = R ✗ (conflict)
∴ Q=3, P=1, T=4

Position: P _ Q T R

Step 4: Apply constraint
- S not adjacent to R (pos 5): S ≠ pos 4 (taken by T) → S at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: P S Q T R

Verification:
✓ R at right extreme end (pos 5)
✓ P second to right of Q: pos[P](=1)-2 = 3 = pos[Q] (south-facing right=lower)
✓ T immediately right of Q (viewer right): pos 3+1 = 4
✓ S not adjacent to R (pos 2, not pos 4)

Answer: P sits at the left extreme end (position 1).

Question 17

Five friends P, S, Q, R and T are sitting in a row facing South. P sits at the right extreme end. S sits second to the right of Q. T sits immediately to the right of Q (from viewer's perspective). R is not adjacent to P. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- P at the right extreme end → Position 5
- S sits second to the right of Q:
South-facing right = viewer's left = lower position: pos[S] = pos[Q] - 2
Possible: Q=3→S=1, or Q=4→S=2
- T sits immediately to the right of Q (viewer's right = higher pos): pos[T] = pos[Q] + 1
If Q=3 → T=4 ✓ (pos 4 free)
If Q=4 → T=5 = P ✗ (conflict)
∴ Q=3, S=1, T=4

Position: S _ Q T P

Step 4: Apply constraint
- R not adjacent to P (pos 5): R ≠ pos 4 (taken by T) → R at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S R Q T P

Verification:
✓ P at right extreme end (pos 5)
✓ S second to right of Q: pos[S](=1)-2 = 3 = pos[Q] (south-facing right=lower)
✓ T immediately right of Q (viewer right): pos 3+1 = 4
✓ R not adjacent to P (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 18

Five friends Q, S, R, T and P are sitting in a row facing South. Q sits at the right extreme end. S sits second to the right of R. P sits immediately to the right of R (from viewer's perspective). T is not adjacent to Q. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- Q at the right extreme end → Position 5
- S sits second to the right of R:
South-facing right = viewer's left = lower position: pos[S] = pos[R] - 2
Possible: R=3→S=1, or R=4→S=2
- P sits immediately to the right of R (viewer's right = higher pos): pos[P] = pos[R] + 1
If R=3 → P=4 ✓ (pos 4 free)
If R=4 → P=5 = Q ✗ (conflict)
∴ R=3, S=1, P=4

Position: S _ R P Q

Step 4: Apply constraint
- T not adjacent to Q (pos 5): T ≠ pos 4 (taken by P) → T at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S T R P Q

Verification:
✓ Q at right extreme end (pos 5)
✓ S second to right of R: pos[S](=1)-2 = 3 = pos[R] (south-facing right=lower)
✓ P immediately right of R (viewer right): pos 3+1 = 4
✓ T not adjacent to Q (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).

Question 19

Five friends T, P, Q, R and S are sitting in a row facing South. T sits at the right extreme end. P sits second to the right of Q. S sits immediately to the right of Q (from viewer's perspective). R is not adjacent to T. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- T at the right extreme end → Position 5
- P sits second to the right of Q:
South-facing right = viewer's left = lower position: pos[P] = pos[Q] - 2
Possible: Q=3→P=1, or Q=4→P=2
- S sits immediately to the right of Q (viewer's right = higher pos): pos[S] = pos[Q] + 1
If Q=3 → S=4 ✓ (pos 4 free)
If Q=4 → S=5 = T ✗ (conflict)
∴ Q=3, P=1, S=4

Position: P _ Q S T

Step 4: Apply constraint
- R not adjacent to T (pos 5): R ≠ pos 4 (taken by S) → R at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: P R Q S T

Verification:
✓ T at right extreme end (pos 5)
✓ P second to right of Q: pos[P](=1)-2 = 3 = pos[Q] (south-facing right=lower)
✓ S immediately right of Q (viewer right): pos 3+1 = 4
✓ R not adjacent to T (pos 2, not pos 4)

Answer: P sits at the left extreme end (position 1).

Question 20

Five friends P, S, Q, R and T are sitting in a row facing South. P sits at the right extreme end. S sits second to the right of Q. T sits immediately to the right of Q (from viewer's perspective). R is not adjacent to P. Who sits at the left extreme end?
Solution Approach:

Step 1: Understanding facing South
When persons face South:
- Their right hand points West (viewer's LEFT) — "right" in the question = lower position number
- Viewer's "right" (higher position) = person's left side

Step 2: Set up diagram (viewer's perspective)
Position: 1(left) 2 3 4 5(right)

Step 3: Apply conditions
- P at the right extreme end → Position 5
- S sits second to the right of Q:
South-facing right = viewer's left = lower position: pos[S] = pos[Q] - 2
Possible: Q=3→S=1, or Q=4→S=2
- T sits immediately to the right of Q (viewer's right = higher pos): pos[T] = pos[Q] + 1
If Q=3 → T=4 ✓ (pos 4 free)
If Q=4 → T=5 = P ✗ (conflict)
∴ Q=3, S=1, T=4

Position: S _ Q T P

Step 4: Apply constraint
- R not adjacent to P (pos 5): R ≠ pos 4 (taken by T) → R at pos 2 ✓

Final Arrangement (all facing South ↓):
Position: S R Q T P

Verification:
✓ P at right extreme end (pos 5)
✓ S second to right of Q: pos[S](=1)-2 = 3 = pos[Q] (south-facing right=lower)
✓ T immediately right of Q (viewer right): pos 3+1 = 4
✓ R not adjacent to P (pos 2, not pos 4)

Answer: S sits at the left extreme end (position 1).
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