If a shopkeeper added 20% on the cost price as marked price and gave 20% discount, then how much was his profit or loss percent?

Correct option is D

​Given:

Marked Price (MP) = Cost Price (CP) + 20%.

Discount = 20%.

Formula Used:
Selling Price (SP):

​$$SP = MP \times (1 - \text{Discount Percentage})$$​​

Loss Percent:

​$$\text{ Loss Percent} = \frac{CP - SP}{CP} \times 100$$​​

Solution:
Let CP = 100: 

MP = 100 + 20% of 100 = 120 

​$$SP = 120 \times (1 - 0.2) = 120 \times 0.8 = 96$$​​

$$\text{Loss Percent} = \frac{100 - 96}{100} \times 100 = 4\%$$​​