A boys rows to a certain place and comes back, but by mistake he covers 2/3rd more distance while coming back. The total time for this journey is 20 hours. The ratio of speed of boat to that of stream is 2 : 1. If the difference between upstream and downstream speed is 24km/hr, then how much time will the man take to reach to starting point from his present position? A) 2hr 13mints B)1hr 30 mins C) 2hr 30mins D)1hr 40 mins