Problem: x does a work in 20 days . y does the same work in 30 days . in how many days they together will do the same work ?
Rationale: "x ' s 1 day ' s work = 1 / 20 y ' s 1 day ' s work = 1 / 30 ( x + y ) ' s 1 day ' s work = ( 1 / 20 + 1 / 30 ) = 1 / 12 both together will finish the work in 12 days . correct option is b"
annotated_formula: inverse(add(divide(const_1, 20), divide(const_1, 30)))