Of the land owned by a farmer, 90 percent was cleared for planting. Of the cleared land, 20 percent was planted with potato and 70 percent of the cleared land was planted with tomato. If the remaining 630 acres of cleared land was planted with corn, how many acres did the farmer own? Choose one.
A) 7000  B) 6800  C) 8000  D) 5400  E) 7100

Rationale: 20 % od 90 % = 18 % , 70 % 0 f 90 % = 63 % so the remaining 90 - 18 - 63 = 9 % = 630 acres or 10 % of 90 % = 9 % - - > 630 / 9 * 100 = 7000 acres answer ( a )
Answer: A