Three table runners have a combined area of 204 square inches. By overlapping the runners to cover 80% of a table of area 175 square inches, the area that is covered by exactly two layers of runner is 24 square inches. What is the area of the table that is covered with three layers of runner?  Choose the correct answer.
A) 18 square inches	B) 20 square inches	C) 24 square inches	D) 28 square inches	E) 30 square inches

Rationale: "total = a + b + c - ( sum of exactly 2 - group overlaps ) - 2 * ( all three ) + neither 80 % * 175 = 204 - 24 - 2 * ( all three ) + 0 2 * ( all three ) = 204 - 24 - 140 all three = 20 answer : b"
Answer: B