A man walks $6 \mathrm{~km}$ at a speed of $1 \frac{1}{2} \mathrm{~km} / \mathrm{hr}$, runs $8 \mathrm{~km}$ at a speed of $2 \mathrm{~km} / \mathrm{hr}$ and goes by bus another $32 \mathrm{~km}$. Speed of the bus is $8 \mathrm{~km} / \mathrm{hr}$. If the speed of the bus is considered as the speed of the man, find the average speed of the man.
(a) $4 \frac{5}{6} \mathrm{~km} / \mathrm{hr}$
(b) $3 \frac{5}{6} \mathrm{~km} / \mathrm{hr}$
(c) $5 \frac{7}{6} \mathrm{~km} / \mathrm{hr}$
(d) None of these