Given Information:
- The trader gains 20% after allowing a discount of 4% on the marked price of an article.

To Find:
- The percentage above the cost price at which the trader has marked the article.

Assumptions:
- Let's assume the cost price of the article is 'C'.
- Let's assume the marked price of the article is 'M'.
- Let's assume the discount given is 'D'.

Calculating the Selling Price:
- The selling price (S) can be calculated using the formula:
S = M - D

Calculating the Gain Percentage:
- The gain percentage (G) can be calculated using the formula:
G = (S - C) / C * 100

Calculating the Marked Price:
- To find the marked price (M), we need to find the selling price (S) first.
- Given that the trader gains 20%, we can write:
G = 20%
G = (S - C) / C * 100
20% = (S - C) / C * 100
20/100 = (S - C) / C
1/5 = (S - C) / C
S - C = C / 5
S = (6/5) * C

Calculating the Discount:
- Given that the discount is 4%, we can write:
D = 4%
D = (4/100) * M
D = (4/100) * (6/5) * C
D = (24/500) * C
D = (12/250) * C

Calculating the Marked Price:
- Now, we can calculate the marked price (M):
M = S + D
M = (6/5) * C + (12/250) * C
M = (30/25) * C + (12/250) * C
M = (120/100) * C + (12/250) * C
M = (120/100 + 12/250) * C
M = (600/500 + 12/250) * C
M = (1200/1000 + 24/500) * C
M = (2400/2000 + 24/500) * C
M = (2400/2000 + 48/1000) * C
M = (2400 + 48) / 2000 * C
M = (2448/2000) * C
M = (1224/1000) * C
M = 1.224 * C

Calculating the Percentage Above the Cost Price:
- The percentage above the cost price is given by:
Percentage Above Cost Price = (M - C) / C * 100
Percentage Above Cost Price = (1.224 * C - C) / C * 100
Percentage Above Cost Price = (0.224 * C) / C * 100
Percentage Above Cost Price = 0.224 * 100
Percentage