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'.
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Question: 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

Answer: b

Question: Problem: a train 250 m long is running at a speed of 45 km / hr . in what time will it pass a bridge 150 m long ?
Options: a ) 45 sec , b ) 42 sec , c ) 32 sec , d ) 48 sec , e ) 25 sec

Answer: c

Question: Problem: a boat goes 130 km downstream in 10 hours , and 75 km upstream in 15 hours . the speed of the stream is ?
Options: a ) 3.5 , b ) 3 , c ) 5 , d ) 4 , e ) 8

Answer:
d