Problem: dan ' s age after 16 years will be 6 times his age 4 years ago . what is the present age of dan ?
Rationale: "let dan ' s present age be x . x + 16 = 6 ( x - 4 ) 5 x = 40 x = 8 the answer is a ."
annotated_formula: divide(add(16, multiply(4, 6)), subtract(6, const_1))