16 boys or 12 women can do a piece of work in 28 days. In how many days will the same work be done by 4 boys and 4 women, if they all work together?

48 days

16 Boys = 12 women

Boys : Women = 12 : 16 = 3 : 4  (Efficiency)

⇒ Total work = 16(3) x 28 days = 48 x 28 = 1344 units,

⇒ Time required by 4 Boys and 4 Women to complete total work = \(\frac{1344}{4(3) + 4(4)}\) = \(\frac{1344}{28}\) = 48 days,      ..(\(\frac{Work}{Efficiency}\) = Time)