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: evaluate 64 / . 08 
Options: a ) 800 , b ) 500 , c ) 505 , d ) none of these , e ) 506
[EX A]: a

[EX Q]: Problem: a company produces on an average 4000 items per month for the first 3 months . how many items it must produce on an average per month over the next 9 months , to average of 4375 items per month over the whole ? 
Options: a ) 4500 , b ) 4600 , c ) 4680 , d ) 4710 , e ) none
[EX A]: a

[EX Q]: Problem: the sum of ages of 5 children born 2 years different each is 40 years . what is the age of the elder child ? 
Options: a ) 12 , b ) 9 , c ) 10 , d ) 16 , e ) 17
[EX A]:
a