A shopkeeper bought some quantity of oranges at the rate of 4 in ₹ 5 and he sold at the rate of 5 in ₹ 4. Find percentage of profit or loss during this transaction.

36%

           Quantity          Price

CP           4 × 5          5 × 5   (make quantity equal)

SP           5 × 4         4 × 4

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

CP              20             25

SP              20             16

Loss % = \(\frac{(25-16)}{25}\) × 100 = 36%