The correct option is
A 25% above the list price
Let the list price be Rs. x
Cost price =20% discount on the list price
That will be 80% of the list price
Cost Price=(80×x)100
Cost Price=4x5
The profit is 25% on the selling price.
So, selling price =125% of the cost price.
=125100×4x5
=x
Let the marked price be Rs y
If the merchant gives 20% discount,
Then 80% of marked price = Selling price
⟹80y100=x
After cross multiplying, we get.
100x=80y
y=5x4
The percentage of the list price at which the merchant marks the goods
=(Marked Price−List Price)100List Price
=(y−x)100x
=(5x4−x)100x=((5x−4x)×1004x)=25%
Hence the price should be 25% above the list price.