A dishonest dealer marks up the price of his goods by 20% and gives a discount of 10% to the customer. He also uses a 900 gram weight instead of a 1 kilogram weight. Find his percentage profit due to these maneuvers?

Explanation:-

He sells only 900 grams when he takes the money for 1 kg.
and
he sells at a 8% profit (20% markup, 10% discount).
Hence, his selling price is Rs. 108 for 900 grams.
% profit = (18/90)*100 = 20%.