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 difference of two numbers is 11 and one - fifth of their sum is 9 . find the numbers . 
Options: a ) 28 and 17 , b ) 27 and 18 , c ) 25 and 15 , d ) 27 and 15 , e ) 25 and 18
[EX A]: a

[EX Q]: Problem: the unit digit in the product ( 784 x 618 x 917 x 463 ) is : 
Options: a ) 5 , b ) 9 , c ) 16 , d ) 2 , e ) 42
[EX A]: d

[EX Q]: Problem: in a group of ducks and cows , the total number of legs are 40 more than twice the number of heads . find the total number of cows . 
Options: a ) 12 , b ) 14 , c ) 16 , d ) 18 , e ) 20
[EX A]:
e