Problem: a is twice as good a work man as b and together they finish the work in 10 days . in how many days a alone can finish the work ?
Rationale: "wc = 2 : 1 2 x + x = 1 / 10 = > x = 1 / 30 2 x = 1 / 15 a can do the work in 15 days . answer : b"
annotated_formula: inverse(divide(inverse(10), add(const_2, const_1)))