A person jogged 10 times along the perimeter of a rectangular field at the rate of 12 kilometers per hour for 30 minutes. If field has a length that is twice its width, find the area of the field in square meters.	Answers.
A) 20,000 square meters	B) 10,000 square meters	C) 30,000 square meters	D) 40,000 square meters	E) 50,000 square meters

Rationale: let us first find the distance d jogged distance = rate * time = ( 12 km / hr ) * 30 minutes = ( 12 km / hr ) * 0.5 hr = 6 km the distance of 6 km corresponds to 10 perimeters and therefore 1 perimeter is equal to 6 km / 10 = 0.6 km = 0.6 * 1000 meters = 600 meters let l and w be the length and width of the field . the length is twice the width . hence l = 2 w the perimeter is 600 meters and is given by 2 ( l + w ) = 600 substitute l by 2 w 2 ( 2 w + w ) = 600 simplify and solve for w 4 w + 2 w = 600 6 w = 600 w = 100 find l l = 2 w = 200 find the area a of the rectangle a = l * w = 200 * 100 = 20,000 square meters correct answer a
Answer: A