Correct Answer - Option 4 : 50%

**Given****∶**

An offer, ‘Buy 3 get 3 free’**.**

**Formula Used****∶**

Discount = Marked Price – Selling Price

Discount % = (Discount / Marked Price) × 100

**Calculation****∶**

Let cost of 1 article be Rs. 100

Total number of articles got = 3 + 3 = 6

Number of articles purchased = 3

M.P. of 6 articles = 100 × 6 = Rs. 600

S.P. of 3 articles = 100 × 3 = Rs. 300

Discount = M.P. – S.P.

⇒ 600 – 300

⇒ Rs. 300

Discount % = (Discount / M. P.) × 100

⇒ (300 / 600) × 100

⇒ 50 %

**∴ The net percentage of discount is 50%.**