The area of a rectangular field is equal to 500 square meters. Its perimeter is equal to 90 meters. Find the width of this rectangle.
Choose the correct answer.
A) 5  B) 10  C) 15  D) 20  E) 25

Rationale: "l * w = 500 : area , l is the length and w is the width . 2 l + 2 w = 90 : perimeter l = 45 - w : solve for l ( 45 - w ) * w = 500 : substitute in the area equation w = 20 and l = 25 correct answer d"
Answer: D