Problem: a can do a piece of work 30 days . b can do work in 45 days . in how many days they will complete the work together ?
Rationale: "lcm = 90 , ratio = 30 : 45 = 2 : 3 no of days = 90 / ( 2 + 3 ) = 90 / 5 = 18 days answer : e"
annotated_formula: divide(const_1, add(divide(const_1, 30), divide(const_1, 45)))