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: the length of the bridge , which a train 130 metres long and travelling at 108 km / hr can cross in 30 seconds , is : 
Options: a ) 200 m , b ) 225 m , c ) 245 m , d ) 170 m , e ) 240 m
[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: the length of the bridge , which a train 145 metres long and travelling at 45 km / hr can cross in 30 seconds , is : 
Options: a ) 200 m , b ) 230 m , c ) 245 m , d ) 250 m , e ) 270 m
[EX A]:
b