the salary of a worker is first increased by 20 % and afterwards reduced by 20 % . what is the net change in the worker ' s salary ?
"let x be the original salary . the final salary is 0.8 ( 1.2 x ) = 0.96 x the answer is a ."
subtract(const_100, subtract(add(20, const_100), divide(multiply(add(20, const_100), 20), const_100)))