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: a vessel of capacity 2 litre has 20 % of alcohol and another vessel of capacity 6 litre had 55 % alcohol . the total liquid of 8 litre was poured out in a vessel of capacity 10 litre and thus the rest part of the vessel was filled with the water . what is the new concentration of mixture ? 
Options: a ) 37 % . , b ) 71 % . , c ) 49 % . , d ) 29 % . , e ) 51 % .

A: a
****
Q: Problem: joe ’ s average ( arithmetic mean ) test score across 4 equally weighted tests was 35 . he was allowed to drop his lowest score . after doing so , his average test score improved to 40 . what is the lowest test score that was dropped ? 
Options: a ) 20 , b ) 25 , c ) 55 , d ) 65 , e ) 80

A: a
****
Q: Problem: the difference of two numbers is 11 and one fifth of their sum is 9 . the numbers are : 
Options: a ) 31 , 20 , b ) 30 , 19 , c ) 29 , 18 , d ) 28 , 17 , e ) none

A:
d
****