paul completes a piece of work in 80 days , rose completes the same work in 120 days . if both of them work together , then the number of days required to complete the work is ?
if a can complete a work in x days and b can complete the same work in y days , then , both of them together can complete the work in x y / x + y days . that is , the required no . of days = 80 × 120 / 200 = 48 days answer is d
inverse(add(divide(const_1, 80), divide(const_1, 120)))