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 trains 140 m and 160 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks . the time ( in seconds ) which they take to cross each other , is : 
Options: a ) 9 , b ) 9.6 , c ) 10 , d ) 10.8 , e ) 7
[EX A]: d

[EX Q]: Problem: buses a and b start from a common bus stop x . bus a begins to travel in a straight line away from bus b at a constant rate of 20 miles per hour . one hour later , bus b begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour . if both buses travel indefinitely , what is the positive difference , in minutes , between the amount of time it takes bus b to cover the exact distance that bus a has covered and the amount of time it takes bus b to cover twice the distance that bus a has covered ? 
Options: a ) 36 , b ) 72 , c ) 132 , d ) 144 , e ) 180
[EX A]: c

[EX Q]: Problem: a train 200 m long is running with a speed of 68 kmph . in what time will it pass a man who is running at 8 kmph in the same direction in which the train is going ? 
Options: a ) 6 sec . , b ) 7 sec . , c ) 9 sec . , d ) 12 sec . , e ) none
[EX A]:
d