Directions (71-75) : Study the following information carefully and answer the question given below:

Seven persons sit in a row facing to the south and they all have different ages. E sits 2nd from one of the extreme ends. Three persons sit between E and the one who is 25 years old. The one who is 25 years old is the only neighbour of A. D sits to the right of C. The Age of D is equal to the total age of his immediate neighbours. C is 15 years old and sits 3 rd to the right of E. B is 10 years older than A and 10 years younger than G who sits at one of the extreme ends. F sits to the right of B who is 1 year younger than E whose age is thrice of age of F.

Who among the following sits 3rd to the left of F?

Correct Answer: G

Let's analyze the given information step-by-step to determine the seating arrangement and ages of all seven persons sitting in a row facing South.

Step 1: Determine the positions of the persons.

There are 7 positions in the row: 1, 2, 3, 4, 5, 6, 7 from Left to Right (facing South).

Note: Since everyone is facing South, Right is to the Left of the page, and Left is to the Right of the page.

1. "E sits 2nd from one of the extreme ends."

This gives two possibilities for E: position 2 or position 6.

2. "Three persons sit between E and the one who is 25 years old."

If E is at position 2, the 25-year-old is at position 6.

If E is at position 6, the 25-year-old is at position 2.

3. "The one who is 25 years old is the only neighbour of A."

For someone to have only one neighbor, that person (A) must sit at an extreme end (position 1 or 7), and the 25-year-old must sit right next to A.

If the 25-year-old is at position 6, then A must be at position 7.

If the 25-year-old is at position 2, then A must be at position 1.

4. "C is 15 years old and sits 3rd to the right of E."

Since persons are facing South, "Right" means moving towards position 1 (Left end of the page).

If E is at position 6, 3rd to the right of E would be position 3 (6 - 3 = 3). C = 15 years old.

If E were at position 2, 3rd to the right would be out of bounds. Thus, E must be at position 6.

Let's summarize the seating arrangement positions so far (from position 1 to 7):

Position 1: A

Position 2: Person (25 years old)

Position 3: C (15 years old)

Position 4: ?

Position 5: ?

Position 6: E

Position 7: ?

5. "G sits at one of the extreme ends."

Since A is at position 1, G must be at position 7.

6. "F sits to the right of B."

The remaining positions are 2, 4, 5. Since F sits to the right of B (towards position 1), B must be at position 4 or 5 and F to his right (lower position index).

Also, we know "D sits to the right of C". C is at position 3, so to the right of C (towards position 1) must be position 2. Therefore, D = position 2 (who is 25 years old).

Since D is at position 2, the remaining positions 4 and 5 must be occupied by F and B.

Since F sits to the right of B, F = position 4 and B = position 5.

Final Seating Order (Left to Right, facing South):

Position 1: A

Position 2: D (25 years old)

Position 3: C (15 years old)

Position 4: F

Position 5: B

Position 6: E

Position 7: G

Step 2: Calculate the ages of the persons.

1. Age of D = 25

2. Age of C = 15

3. "The Age of D is equal to the total age of his immediate neighbours."

D's immediate neighbors are A and C.

$\mathrm{Age\; of\; D}=\mathrm{Age\; of\; A}+\mathrm{Age\; of\; C}$

$25=\mathrm{Age\; of\; A}+15\Rightarrow \mathrm{Age\; of\; A}=10$

4. "B is 10 years older than A..."

$\mathrm{Age\; of\; B}=10+10=20$

5. "...and 10 years younger than G"

$\mathrm{Age\; of\; G}=20+10=30$

6. "B who is 1 year younger than E"

$\mathrm{Age\; of\; E}=20+1=21$

7. "...whose age is thrice of age of F." (E's age is 3 times F's age)

$\mathrm{Age\; of\; F}=\frac{21}{3}=7$

Step 3: Answer the specific question.

"Who among the following sits 3rd to the left of F?"

F is at position 4. Facing South, "Left" means moving towards position 7 (Right side of the page).

3rd to the left of position 4 is position $4+3=7$.

The person sitting at position 7 is G.