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: two passenger trains start at the same hour in the day from two different stations and move towards each other at the rate of 24 kmph and 21 kmph respectively . when they meet , it is found that one train has traveled 60 km more than the other one . the distance between the two stations is ? 
Options: a ) 288 , b ) 540 , c ) 877 , d ) 278 , e ) 178
[EX A]: b

[EX Q]: Problem: 8 persons can build a wall 140 m long in 42 days . in how many days can 30 persons complete a similar wall 100 m long ? 
Options: a ) 12 , b ) 10 , c ) 8 , d ) 6 , e ) 5
[EX A]: c

[EX Q]: Problem: two trains 121 meters and 153 meters in length respectively are running in opposite directions , one at the rate of 80 km and the other at the rate of 65 kmph . in what time will they be completely clear of each other from the moment they meet ? 
Options: a ) 7.19 , b ) 6.8 , c ) 7.2 , d ) 7.15 , e ) 7.11
[EX A]:
b