Problem: each factor of 220 is inscribed on its own plastic ball , and all of the balls are placed in a jar . if a ball is randomly selected from the jar , what is the probability that the ball is inscribed with a multiple of 55 ?
Rationale: "the # of factors 220 has is 12 ; so out of 12 factors only three are multiples of 55 : 55 , 110 and 220 , itself ; so , the probability is 3 / 12 = 1 / 4 . answer : e ."
annotated_formula: divide(divide(choose(55, const_1), 55), power(const_3, const_2))