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 cyclist bikes x distance at 20 miles per hour and returns over the same path at 16 miles per hour . what is the cyclist ' s average rate for the round trip in miles per hour ? 
Options: a ) 17.6 , b ) 17.3 , c ) 8.6 , d ) 17.2 , e ) 9.0
[EX A]: a

[EX Q]: Problem: what is the length of a bridge ( in meters ) , which a train 156 meters long and travelling at 45 km / h can cross in 30 seconds ? 
Options: a ) 203 , b ) 211 , c ) 219 , d ) 227 , e ) 235
[EX A]: c

[EX Q]: Problem: a man swims downstream 30 km and upstream 12 km taking 3 hours each time , what is the speed of the man in still water ? 
Options: a ) 8 , b ) 7 , c ) 5 , d ) 2 , e ) 4
[EX A]:
b