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

[EX Q]: Problem: a start walking from a place at a uniform speed of 4 kmph in a particular direction . after half an hour , b starts from the same place and walks in the same direction as a at a uniform speed and overtakes a after 1 hour 48 minutes . find the speed of b .
Options: a ) 4.7 kmph , b ) 4.6 kmph , c ) 4 kmph , d ) 7 kmph , e ) 5.3 kmph
[EX A]: b

[EX Q]: Problem: a train covers a distance of 18 km in 3 min . if it takes 4 sec to pass a telegraph post , then the length of the train is ?
Options: a ) 370 , b ) 380 , c ) 390 , d ) 400 , e ) 410
[EX A]:
d