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: in what time will a train 140 meters long cross an electric pole , if its speed is 210 km / hr 
Options: a ) 5 seconds , b ) 4.5 seconds , c ) 3 seconds , d ) 2.4 seconds , e ) none of these
[EX A]: d

[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: a person started from point a to point b and returned back to a with a speed of 60 kmh . if the distance between a and b is 120 km , calculate the time he travelled 
Options: a ) 4 hours , b ) 2 hours , c ) 3 hours , d ) 6 hours , e ) 5 hours
[EX A]:
a