Let Benny's salary = $ K
But kenny earns 142% of Benny's Salary
So, Kenny's salary = 142%of K
Kenny's salary =K

Kenny's salary = 1.42K
Kenny's income exceeds Benny's by =1.42K - K =$0.42 K
% by which Kenny's salary exceeds by Benny's =

% by which Kenny's salary exceeds by Benny's = 42%