A man and a woman, working together can do a work in 66 days. The ratio of their working efficiencies is 3 : 2. In how many days 6 men and 2 women working together can do the same work?

15

M + W = 66 days,

M : W = 3 : 2  (Efficiency)

⇒ Time taken  by 6 men and 2 women working together can do the same work in = \(\frac{330}{6(3) + 2(2)}\) = \(\frac{330}{6(3) + 2(2)}\) = \(\frac{330}{18 + 14}\) = \(\frac{330}{22}\) = 15 days.   ..(\(\frac{Work}{Efficiency}\) = Time)