The marked price of a refrigerator is ₹ 12,000 and GST paid by the customer is ₹ 2,160. The rate of GST is:

Let rate of GST be x.

Given,

Marked price of refrigerator = ₹ 12,000

GST paid = ₹ 2,160

GST amount = $\frac{\text{Rate}}{100}$ × Marked price

⇒ 2160 = $\frac{x}{100}$ × 12000

⇒ 2160 = 120x

⇒ x = $\frac{2160}{120}$

⇒ x = 18%

Hence, option 3 is the correct option.