A man can cover a certain distance in 3 hours 36 minutes If he walks at the rate of 5 km/hr. If he covers the same distance on cycle at the rate of 24 km/hr, then the time taken by him in minutes is :

Total distance covered by man in 3 hours 36 minutes is :
$$\eqalign{ & = 5 \times 3\frac{{36}}{{60}} = 5 \times 3\frac{3}{5} \cr & = 5 \times \frac{{18}}{5} \cr & = 18{\text{ km}} \cr} $$
18 km is covered at an speed of 24 km/hr
∴ Time taken is :
$$\eqalign{ & = \frac{{18}}{{24}} \cr & = \frac{3}{4} \times 60 \cr & = 45{\text{ minutes}} \cr} $$