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: 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
[EX A]: a

[EX Q]: Problem: find the smallest positive integer n such that 11 n - 1 is divisible by 105 . 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 7
[EX A]: d

[EX Q]: Problem: the difference between a number and its two - fifth is 510 . what is 5 % of that number ? 
Options: a ) 425 , b ) 300 , c ) 255 , d ) 300 , e ) 400
[EX A]:
a