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: a train 605 m long is running with a speed of 60 km / hr . in what time will it pass a man who is running at 6 km / hr in the direction opposite to that in which the train is going ? 
Options: a ) 81 , b ) 16 , c ) 33 , d ) 54 , e ) 12
[EX A]: c

[EX Q]: Problem: the ratio between the speeds of two trains is 7 : 8 . if the second train runs 400 km in 4 hours , what is the the speed of the first train ? 
Options: a ) 87.0 , b ) 87.5 , c ) 87.2 , d ) 87.1 , e ) 87.4
[EX A]: b

[EX Q]: Problem: a can do a piece of work in 20 days , and b can do it in 15 days . how long will they take if both work together ? 
Options: a ) 7 days , b ) 8.6 days , c ) 13 days , d ) 5.6 days , e ) 10 days
[EX A]:
b