A rectangular field has to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 680 sq. feet, how many feet of fencing will be required?	Options:
A) 80 feet	B) 85 feet	C) 83 feet	D) 88 feet	E) 90 feet

Rationale: given that area of the field = 680 sq . feet = > lb = 680 sq . feet length ( l ) = 20 feet = > 20 × b = 680 = > b = 680 / 20 = 34 feet required length of the fencing = l + 2 b = 20 + ( 2 × 34 ) = 88 feet answer is d .
Answer: D