two numbers are respectively 20 % and 50 % more than a third number . the percentage that is first of the second is ?
"i ii iii 120 150 100 150 - - - - - - - - - - 120 100 - - - - - - - - - - - ? = > 80 % answer : b"
subtract(const_100, multiply(divide(add(20, const_100), add(50, const_100)), const_100))