Walking $${\frac{6}{7}}$$ th of his usual speed, a man is 12 minutes too late. The usual time taken by him to cover that distance is :

New speed = $$\frac{6}{7}$$ of usual speed
New time = $$\frac{7}{6}$$ of usual time
$$\therefore \left( {\frac{7}{6}{\text{ of usual time}}} \right) - $$    $$\left( {{\text{usual time}}} \right)$$   $$ = \frac{1}{5}{\text{ hr}}$$
$$\eqalign{ & \Rightarrow \frac{1}{6}{\text{ of usual time = }}\frac{1}{5}{\text{ hr}} \cr & \Rightarrow {\text{usual time = }}\frac{6}{5}{\text{ hr}} \cr & \Rightarrow {\text{usual time = 1 hr 12 min}} \cr} $$