A statue is being carved by a sculptor. The original piece of marble weighed 180 kg. In the first week 28 percent is cut away. In the second week 18 percent of the remainder is cut away. In the third week the statue is completed when 20 percent of the remainder is cut away. What is the weight of the final statue?
Choose one:  A) 105 kg  B) 85 kg  C) 108 kg  D) 125 kg  E) 117 kg

Rationale: "b 85 kg 180 ã — 0.72 ã — 0.82 ã — 0.8 = 85 kg ."
Answer: B