A dealer offers a cash discount of 10% and still makes a profit of 20% when he further allows 45 articles to be sold at the cost price of 40 articles to a particular sticky bargainer. How much percent above the cost price were his articles listed?  Pick one
A) 40 % B) 50 % C) 55 % D) 80 % E) 90 %

Rationale: "given cash discount - 10 % profit - 20 % items sold - 45 price sold at = list price of 40 assume list price = $ 10 total invoice = $ 400 - 10 % cash discount = $ 360 let cost price of 45 items be x so total cost = 45 * x given the shopkeeper had a profit of 20 % 45 * x * 120 / 100 = 360 or x = $ 20 / 3 = $ 6 + ( 2 / 3 ) which means his products were listed at $ 10 which is a 50 % markup over $ 6 + ( 2 / 3 ) answer b"
Answer: B