Aman sells his goods at a certain price, 20% of which is profit. If the price at which he buys the goods increases by 10% and he sells them at a 9% higher price, then what will be his profit percentage?

23.8%

Let SP = 100

20% of it is profit 

                   SP               Profit        CP

                   100               20           80

             +9%  ↓                                ↓ +10%                P% = \(\frac{21}{88}\) × 100

                   109                              88                              = 23.8%

                 Diff 109 - 88 = 21