How long will a boy take to run round a square field of side 50 meters, if he runs at the rate of 10km/hr?	Choose the correct option
A) 52 sec	B) 45 sec	C) 72 sec	D) 25 sec	E) 39 sec

Rationale: "speed = 10 km / hr = 10 * 5 / 18 = 25 / 9 m / sec distance = 50 * 4 = 200 m time taken = 200 * 9 / 25 = 72 sec answer is c"
Answer: C