Given: One man and one Woman together can complete a piece of work = 12 days A man can complete the work = 30 days Concept used: Total work = LCM Formula used: Efficiency = Work/Time Calculation Let efficiency of a man and a woman be M and F respectively Total efficiency of a man and a woman = M + F Work done a man and a woman in 12 days = 12(M + F) Total work done a man in 30 days = 30M According to the question, ⇒ 12(M + F) = 30M ⇒ 12 M + 12F = 30 M ⇒ 12F = 18 M ⇒ F ∶ M = 3 ∶ 2 Total work = total efficiency × together work done Total work = 5 × 12 = 60 One woman completes the work = 60/3 = 20 days ∴ One woman completes the work in 20 days