Correct Answer - Option 3 : 50%

**Given:**

Cost price of the article = Rs. x

Selling price of the article = Rs. 75

Profit% = x%

**Formula used:**

Profit% = [(S.P - C.P)/C.P] × 100

**Calculation:**

According to the question,

x = [(75 - x)/x] × 100

⇒ x^{2} = 7500 - 100x

⇒ x(x + 100) = 7500

⇒ x(x + 100) = 50(50 + 100)

On comparing both sides,

x = 50

**∴ The value of x is 50.**