Problem: a can do a job in 18 days and b can do it in 30 days . a and b working together will finish twice the amount of work in - - - - - - - days ?
Rationale: "1 / 18 + 1 / 30 = 8 / 90 = 4 / 45 45 / 4 = 11 ¼ * 2 = 22 ½ days answer : b"
annotated_formula: add(divide(const_1, 18), divide(const_1, 30))