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'.

[EX Q]: Problem: if x : y = 3 : 5 , find the value of ( 2 x + 4 y ) : ( 3 x – y ) 
Options: a ) 13 : 2 , b ) 11 : 2 , c ) 13 : 3 , d ) 13 : 4 , e ) 13 : 5
[EX A]: a

[EX Q]: Problem: for a certain exam , a score of 60 was 2 standard deviations below mean and a score of 100 was 3 standard deviations above mean . what was the mean score for the exam ? 
Options: a ) 74 , b ) 76 , c ) 78 , d ) 80 , e ) 82
[EX A]: b

[EX Q]: Problem: 90 % of the population of a village is 36000 . the total population of the village is ? 
Options: a ) 26799 , b ) 24000 , c ) 26682 , d ) 29973 , e ) 40000
[EX A]:
e