A shopkeeper promises to sell his goods at 5% profit, but he uses 25% less weight while selling. Find the profit percentage?

40%

Assume quantity = 1000 g

                         1000 g

                            ↓

              ------------------------

 -25%    ↓                              ↓  +5%

           750 g                       1050 g

            ↓                               ↓

            ⇒   different = 300g  ⇐

Profit = \(\frac{300}{750}\) × 100

         = 40 %

750 g thing is sold after reducing 25 % weight