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: the sum of three consecutive multiples of 3 is 108 . what is the largest number ? 
Options: a ) 36 , b ) 39 , c ) 33 , d ) 30 , e ) 42
[EX A]: b

[EX Q]: Problem: a father said his son , ` ` i was as old as you are at present at the time of your birth . ` ` if the father age is 32 now , the son age 5 years back was 
Options: a ) 11 , b ) 17 , c ) 11 , d ) 19 , e ) 99
[EX A]: a

[EX Q]: Problem: exactly 3 / 8 of the people in the room are under the age of 21 , and exactly 5 / 12 of the people in the room are over the age of 65 . if the total number of the people in the room is greater than 50 and less than 100 , how many people in the room are under the age of 21 ? 
Options: a ) 21 , b ) 36 , c ) 39 , d ) 60 , e ) 65
[EX A]:
b