Correct Answer - Option 4 : 400%

**Given:**

15% of (x + y) = 25% of (x - y)

**Formula used:**

Percentage = (Obtained value/Total value) × 100

**Calculation:**

15% of (x + y) = 25% of (x - y)

⇒ 15(x + y) = 25(x - y)

⇒ 15x + 15y = 25x - 25y

⇒ 15y + 25y = 25x - 15x

⇒ 40y = 10x

⇒ x = 4y

Now, Percentage = (Obtained value/Total value) × 100

⇒ (x/y) × 100

⇒ (4y/y) × 100

⇒ 400%