A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 80 sq. feet, how many feet of fencing will be required?
Choose one
A) 28	B) 40	C) 68	D) 88	E) 78

Rationale: "we have : l = 20 ft and lb = 80 sq . ft . so , b = 4 ft . length of fencing = ( l + 2 b ) = ( 20 + 8 ) ft = 28 ft . answer : a"
Answer: A