a) 4 days
b) 5 days
c) 3 days
d) 2 days

Answer: c
Explanation:
$$\eqalign{ & {\text{3m}} \times {\text{16}} = {\text{6w}} \times {\text{16}} \cr} $$
$$\frac{{\text{m}}}{{\text{w}}} = $$ $$\frac{{2 \to {\text{Efficiency of men}}}}{{1 \to {\text{Efficiency of women}}}}$$
$$\eqalign{ & {\text{Total work}} = 3 \times 2 \times 16 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 96{\text{ units}} \cr} $$
$${\text{One day work of}}$$    $$\left( {{\text{12m}} + {\text{8w}}} \right)$$
$$\eqalign{ & = 12 \times 2 + 8 \times 1 \cr & = 32{\text{ units}} \cr} $$
$${\text{Total time taken by}}$$    $$\left( {{\text{12m}} + {\text{8w}}} \right)$$
$$\eqalign{ & = \frac{{96}}{{32}} \cr & = 3{\text{ days}} \cr} $$