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: a man can row upstream at 15 kmph and downstream at 25 kmph , and then find the speed of the man in still water ? 
Options: a ) 27 , b ) 29 , c ) 30 , d ) 20 , e ) 24
[A]: d


[Q]: Problem: the curved surface of a sphere is 64 π cm 2 . find its radius ? 
Options: ['a ) 8', 'b ) 3', 'c ) 4', 'd ) 9', 'e ) 7']
[A]: c


[Q]: Problem: an aeroplane covers a certain distance of 420 kmph in 6 hours . to cover the same distance in 4 2 / 3 hours , it must travel at a speed of ? 
Options: a ) 450 km , b ) 480 km , c ) 500 km , d ) 540 km , e ) 590 km
[A]:
d