Walking 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 :

Answer: Option B

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