A. 14 min 10 seconds lost

B. 13 min 50 seconds lost

C. 13 min 20 second gained

D. 14 min 40 second gained

A man in a train notices that he can count 21 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed in the train travelling?

A Boat running downstream covers a distance of 16 km in 2 hours while for covering the same Distance upstream it takes 4 hours. What is the speed of the boat in still water?