A shopkeeper normally makes a profit of 20% in a certain transaction; he weighed 900 gm instead of 1 kg due to an error in the weighing machine. If he charges 15% less than what he normally charges, then what is his actual profit or loss percentage?

Given:

A shopkeeper normally makes a profit of 20% in a certain transaction; he weighed 900 gm instead of 1 kg due to an error in the weighing machine. If he charges 15% less than what he normally charges, then what is his actual profit or loss percentage?

Formula used:

Profit Percentage = \(\left(\dfrac{\text{Selling Price} - \text{Cost Price}}{\text{Cost Price}}\right) \times 100\)

Calculation:

Let the Cost Price (CP) of 1 kg be ₹100.

Selling Price (SP) with 20% profit = ₹120.

Due to the error, the shopkeeper weighs 900 gm instead of 1 kg. Hence, he sells 900 gm at 15% less than the normal price.

New Selling Price (NSP) = ₹120 × 0.85 = ₹102.

Effective Cost Price (ECP) of 900 gm = ₹90 (since 900 gm of ₹100/kg).

⇒ Profit = NSP - ECP = ₹102 - ₹90 = ₹12.

⇒ Profit Percentage = \(\left(\dfrac{12}{90}\right) \times 100\)

⇒ Profit Percentage = \(\dfrac{12}{90} \times 100 = 13.33\%\)

∴ The correct answer is option (1).