In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[Q]: Problem: in a river flowing at 2 km / hr , a boat travels 40 km upstream and then returns downstream to the starting point . if its speed in still water be 6 km / hr , find the total journey time . 
Options: a ) 10 hours , b ) 12 hours , c ) 14 hours , d ) 15 hours , e ) none of these
[A]: d


[Q]: Problem: a man is 24 years older than his son . in six years , his age will be twice the age of his son . the present age of the son is 
Options: a ) 14 years , b ) 28 years , c ) 20 years , d ) 22 years , e ) none
[A]: e


[Q]: Problem: a batsman makes a score of 50 runs in the 17 th inning and thus increases his averages by 2 . what is his average after 17 th inning ? 
Options: a ) 39 , b ) 18 , c ) 42 , d ) 40.5 , e ) 41.5
[A]:
b