A shopkeeper gives a discount of 12% on the purchase of 10 kg of sugar. The cost price of the sugar is ₹30/kg, and the marked price is ₹38/kg. The weighing machine of the shopkeeper is faulty, and it shows weight of 1 kg when the actual weight is 900 grams. Find the percentage profit of the shop keeper (rounded off to two decimal places).

The correct answer is 23.85%.

Let's carefully analyze all the factors at play: the discount on marked price, the cost price, and the faulty weighing machine — each of which affects the shopkeeper's actual profit.

Step 1: Identify the given information

Cost Price (CP) per kg = ₹30
Marked Price (MP) per kg = ₹38
Discount offered = 12%
Apparent quantity sold (as shown by machine) = 10 kg
Actual quantity given per "1 kg" reading = 900 grams = 0.9 kg

Step 2: Calculate the Selling Price per kg (after discount)

The shopkeeper gives a 12% discount on the marked price:

SP per kg = MP × (1 - Discount%)
SP per kg = 38 × (1 - 0.12)
SP per kg = 38 × 0.88
SP per kg = ₹33.44

Step 3: Calculate Total Revenue received from the customer

The customer buys what the machine shows as 10 kg, and pays accordingly:

Total Revenue = SP per kg × Apparent weight
Total Revenue = 33.44 × 10 = ₹334.40

Step 4: Calculate Actual Weight of Sugar given to the customer

Since the machine shows 1 kg when it actually dispenses only 900 g, for every kg shown, only 0.9 kg is actually given:

Actual weight given = 10 × 900 g = 9000 g = 9 kg

Step 5: Calculate the actual Cost Price of sugar given

Total CP = Actual weight × CP per kg
Total CP = 9 × 30 = ₹270

Step 6: Calculate Profit and Profit Percentage

Profit = Total Revenue - Total Cost
Profit = 334.40 - 270 = ₹64.40

Profit % = \frac{\mathrm{Profit}}{\mathrm{Total\; CP}}\times 100

Profit % = \frac{64.40}{270}\times 100 = 23.85%

Summary of factors boosting the shopkeeper's profit:

1. The marked price (₹38) is already higher than the cost price (₹30).
2. Even after giving a 12% discount, the SP (₹33.44) remains above the CP (₹30).
3. The faulty machine further reduces the actual sugar delivered (9 kg instead of 10 kg), lowering the real cost while the customer pays for the full 10 kg.

Therefore, the percentage profit of the shopkeeper (rounded to two decimal places) is 23.85%.