A park square in shape has a 3 metre wide road inside it running along its sides. The area occupied by the road is 1764 square metres. What is the perimeter along the outer edge of the road?  Choose the correct choice from the following answers.
A) 576 metres	B) 589 metres	C) 600 metres	D) 700 metres	E) none

Rationale: solution let the length of the outer edges be x metres . then , length of the inner edge = ( x - 6 ) m . ∴ x 2 - ( x - 6 ) 2 = 1764 ‹ = › x 2 - ( x 2 - 12 x + 36 ) = 1764 ‹ = › 12 x = 1800 ‹ = › x = 150 . ∴ required perimeter = ( 4 x ) m ‹ = › ( 4 x 150 ) m = 600 m . answer c
Answer: C