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'.

[Q]: Problem: a train overtakes two person who are walking in the same direction in which the train is going , at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively . the length of the train is : 
Options: a ) 45 m , b ) 50 m , c ) 54 m , d ) 72 m , e ) none of these
[A]: b


[Q]: Problem: excluding stoppages , the speed of a train is 30 kmph and including stoppages it is 21 kmph . of how many minutes does the train stop per hour ? 
Options: a ) 16 , b ) 17 , c ) 12 , d ) 15 , e ) 18
[A]: e


[Q]: Problem: x and y can do a piece of work in 20 days and 12 days respectively . x started the work alone and then after 4 days y joined him till the completion of the work . how long did the work last ? 
Options: a ) 6 days , b ) 10 days , c ) 15 days , d ) 16 days , e ) 20 days
[A]:
b