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'.

Problem: mary ' s income is 60 % more than tim ' s income and tim ' s income is 10 % less than juan ' s income . what % of juan ' s income is mary ' s income . 
Options: a ) 144 % , b ) b . 120 % , c ) 96 % , d ) 80 % , e ) 64 %
a

Problem: in n is a positive integer less than 200 , and 18 n / 60 is an integer , then n has how many different positive prime factors ? 
Options: a ) 2 , b ) 3 , c ) 5 , d ) 6 , e ) 8
a

Problem: a total of 520 players participated in a single tennis knock out tournament . what is the total number of matches played in the tournament ? ( knockout means if a player loses , he is out of the tournament ) . no match ends in a tie . 
Options: a ) 511 , b ) 519 , c ) 256 , d ) 255 , e ) 1023

b