A salesman sells a commodity at 10% profit. If he had bought it at 10% less and sold it for Rs 4 less, then he would have gained (\frac{50}{3})% . The cost price of the commodity is -

Let cost price be x. Original selling price = 1.1x. In the new scenario, cost price = 0.9x and selling price = 1.1x - 4, giving a profit of 50/3%. This means new SP = 0.9x × (7/6) = 1.05x. Equating: 1.1x - 4 = 1.05x, so 0.05x = 4, giving x = 80. The distractors (120, 60, 90) come from incorrect equation setup or calculation errors.