Bill made a profit of 10% by selling a product. If he had purchased that product for 10% less and sold it at a profit of 30%, he would have received $ 35 more. What was his original selling price?
Choose the correct choice from the following choices.
A) $ 180	B) $ 280	C) $ 420	D) $ 550	E) $ 700

Rationale: "let p be the original purchase price of the product . bill originally sold the product for 1.1 * p . in the second scenario , the purchase price is 0.9 * p . a 30 % profit means the selling price would be 1.3 * 0.9 * p = 1.17 * p thus , according to the information in the question , 1.17 p - 1.1 p = 35 0.07 = 35 p = 500 the original selling price was 500 * 1.1 = 550 . the correct answer is d ."
Answer: D