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'.

[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
[A]: b

[Q]: Problem: how many shots of 1 cm radius can be prepared from a sphere of 4 cm radius ?
Options: a ) 33 , b ) 88 , c ) 27 , d ) 64 , e ) 99
[A]: d

[Q]: Problem: a person travels equal distances with speeds of 7 km / hr , 8 km / hr and 9 km / hr and takes a total time of 47 minutes . the total distance is ?
Options: a ) 6 km , b ) 3 km , c ) 7 km , d ) 9 km , e ) 2 km
[A]:
a