In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[EX Q]: Problem: mary can do a piece of work in 28 days . rosy is 40 % more efficient than mary . the number of days taken by rosy to do the same piece of work is ? 
Options: a ) 22 , b ) 24 , c ) 20 , d ) 25 , e ) 27
[EX A]: c

[EX Q]: Problem: in what time will a train 100 meters long cross an electric pole , if its speed is 162 km / hr 
Options: a ) 8.5 seconds , b ) 2.22 seconds , c ) 3.5 seconds , d ) 2.5 seconds , e ) 2.6 seconds
[EX A]: b

[EX Q]: Problem: a man swims downstream 28 km and upstream 16 km taking 4 hours each time , what is the speed of the man in still water ? 
Options: a ) 6.5 , b ) 8.6 , c ) 7.5 , d ) 9.2 , e ) 5.5
[EX A]:
e