A man walking at the speed of 4 kmph crosses a square field diagonally in 3 minutes. The area of the field is:	Options:
A) 18000 m 2 B) 20000 m 2 C) 19000 m 2 D) 25000 m 2 E) 15000 m 2

Rationale: length of the diagonal = distance covered in 3 min . at 4 km / hr . = ( 4000 / 60 * 3 ) = 200 m . therefore , area of the field = 1 / 2 * diagonal 2 = ½ * 200 * 200 = 20000 m 2 answer : b
Answer: B