A dishonest dealer marks up the price of his goods by 20% and gives a discount of 10% to the customer. Besides, he also cheats both his supplier and his buyer by 100 grams while buying or selling 1 kilogram. Find the percentage profit earned by the shopkeeper?

Answer: Option C

While buying,
He buys 1100 gram instead of 1000 gram.
Suppose he bought 1100 grams for Rs. 1000.

While selling,
He sells only 900 grams when he takes the money for 1 kg.
Now, according to the problem,
he sells at a 8% profit (20% markup, 10% discount).
Hence, his selling price is Rs. 1080 for 900 grams.
Now,
1100 grams for Rs. 1000
Hence, 1188 grams for Rs. 1080
Selling: 900 grams for Rs. 1080
Hence, % profit = $$\frac{288}{900}$$  × 100 = 32%
(using goods left by goods sold formula).