Let the CP of one articles be Rs. 1
Then, the SP be Rs. 1.25
Again the new SP be (1.25) x 1.2 = 1.5
Now, if he sell initially 100 articles, then
CP = 100 x 1 = Rs. 100
SP = 100 x 1.25 = Rs. 125
New SP = 75 x 1.5 = 112.5 (since 25% articles were abducted)
Therefore, new profit percentage = 12.5%