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 boat covers a certain distance downstream in 1 hour , while it comes back in 1 ½ hours . if the speed of the stream be 3 kmph , what is the speed of the boat in still water ? 
Options: a ) 12 kmph , b ) 13 kmph , c ) 14 kmph , d ) 15 kmph , e ) none
[EX A]: d

[EX Q]: Problem: 42 persons can repair a road in 12 days , working 5 hours a day . in how many days will 30 persons , working 6 hours a day , complete the work ? 
Options: a ) 10 , b ) 16 , c ) 13 , d ) 14 , e ) 19
[EX A]: d

[EX Q]: Problem: suresh can complete a job in 15 hours . ashutosh alone can complete the same job in 25 hours . suresh works for 9 hours and then the remaining job is completed by ashutosh . how many hours will it take ashutosh to complete the remaining job alone ? 
Options: a ) 4 , b ) 5 , c ) 6 , d ) 10 , e ) none of these
[EX A]:
d