Problem: a can do a piece of work in 20 days and b alone can do it in 10 days . b works at it for 5 days and then leaves . a alone can finish the remaining work in
Rationale: "explanation : b ' s 5 days work = 1 / 10 ∗ 5 = 1 / 2 remaining work = 1 − 1 / 2 = 1 / 2 a can finish work = 20 ∗ 1 / 2 = 10 days option a"
annotated_formula: divide(const_1, add(divide(const_1, 20), divide(const_1, 10)))