Problem: a , b and c can do a piece of work in 14 , 30 and 40 days respectively . they start the work together but c leaves 4 days before the completion of the work . in how many days is the work done ?
Rationale: "x / 14 + x / 30 + x / 40 = 1 x = 7.7 days answer : b"
annotated_formula: add(subtract(subtract(14, subtract(40, 30)), 4), const_1)