A tradesman marks his goods at 25% above the cost price and allows purchasers a discount of 252 %, his profit is:

Let his CP = Rs. 100.
Marked Price = 100 + 25% of 100 = 125.
Now, discount = $$\frac{25}{2}$$% on MP
So, SP = 125 - $$\frac{25}{2}$$% of 125 = Rs. 109.375.
%Gain = 9.375%.

Alternatively use graphic change method:
100(CP) == 25% Up ⇒ 125(MP) == 12.5%down ⇒ 109.375
%Profit = 9.375%