1.  How long will a boy take to run round a square field of side 35 metres, if he runs at the rate of 9 km/hr ?
A. 50 sec
B. 52 sec
C. 54 sec
D. 56 sec

Answer: Option D

Explanation:

Speed = 9 km/hr = (9 x 5/18) m/sec
          = 5/2 m/sec

Distance = (35 x 4) m = 140 m

Time taken = (140 x 2/5 ) sec = 56 sec