A girl walking at the rate of 9 Km per hour crosses a square field diagonally in 12 seconds. The area of the field is:
Choose the correct choice: A) 430 sq . m B) 425 sq . m C) 450 sq . m D) 475 sq . m E) 350 sq . m

Rationale: distance covered in ( 9 × 1000 ) / ( 3600 ) × 12 = 30 m diagonal of squarre field = 30 m . area of square field = 30 ( power ) 2 / 2 = 900 / 2 = 450 sq . m answer is c .
Answer: C