Problem: let f ( x , y ) be defined as the remainder when ( x – y ) ! is divided by x . if x = 16 , what is the maximum value of y for which f ( x , y ) = 0 ?
Rationale: "the question is finding y such that ( 16 - y ) ! is a multiple of 16 . that means we need to have 2 ^ 4 in ( 16 - y ) ! 6 ! is the smallest factorial number with 2 ^ 4 as a factor . 16 - y = 6 y = 10 the answer is b ."
annotated_formula: subtract(16, multiply(const_2, divide(divide(16, const_2), add(const_1, const_4))))