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: what is 2 3 / 4 - 1 2 / 5 divided by 2 / 3 - 1 / 3 ? 
Options: a ) 17 / 36 , b ) 36 / 17 , c ) 7 / 6 , d ) 27 / 20 , e ) 51 / 44
[A]: d


[Q]: Problem: students at a school were on average 180 cm tall . the average female height was 170 cm , and the average male height was 184 cms . what was the ratio s of men to women ? 
Options: a ) 5 : 2 , b ) 5 : 1 , c ) 4 : 3 , d ) 4 : 1 , e ) 3 : 1
[A]: a


[Q]: Problem: in a river flowing at 2 km / hr , a boat travels 64 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 ) 24 hours , e ) none of these
[A]:
d