The area of a square field is 900 km2. How long will it take for a horse to run around at the speed of 12 km/h ?
Choose one: A) 12 h B) 10 h C) 8 h D) 6 h E) none of these

Rationale: explanation area of field = 900 km 2 . then , each side of field = √ 900 = 30 km distance covered by the horse = perimeter of square field = 30 × 4 = 120 km ∴ time taken by horse = distances / peed = 120 / 12 = 10 h answer b
Answer: B