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 train 110 meters long completely crosses a 280 meters long bridge in 38 seconds . what is the speed of the train is ?
Options: a ) 32 , b ) 45 , c ) 40 , d ) 66 , e ) 09
[EX A]: c

[EX Q]: Problem: when working alone , painter w can paint a room in 2 hours , and working alone , painter x can paint the same room in r hours . when the two painters work together and independently , they can paint the room in 3 / 4 of an hour . what is the value of r ?
Options: a ) 3 / 4 , b ) 1 [ 1 / 5 ] , c ) 1 [ 2 / 5 ] , d ) 1 [ 3 / 4 ] , e ) 2
[EX A]: b

[EX Q]: Problem: a worker can load one truck in 5 hours . a second worker can load the same truck in 8 hours . if both workers load one truck simultaneously while maintaining their constant rates , approximately how long , in hours , will it take them to fill one truck ?
Options: a ) 2.5 , b ) 2.7 , c ) 2.9 , d ) 3.1 , e ) 3.3
[EX A]:
d