A shirt goes on sale for 80% of its original price. One week later, the sale price is marked down 10%. The final price is what percent of the original price?  Select.
A) 72 %  B) 70 %  C) 52 %  D) 50 %  E) 28 %

Rationale: "just assume original price is 100 . sale price = 80 then it is marked down by 10 % = 80 - 8 = 72 . hence it is 72 % of the original price . hence answer is a"
Answer: A