Walking 6/7th of his usual speed, a man is 12 minutes too late. The usual time taken by him to cover that distance is : Choices:
A) 1 hr 20 min  B) 1 hr 11 min  C) 1 hr 12 min  D) 1 hr 30 min  E) None of these
Explanation :   New speed = 6/7 of usual speed.   New time = 7/6 of usual time   =&gt; [7/6 of usual time] - (usual time) = 1/5 hr.   =&gt; 1/6 of usual time = 1/5 hr   =&gt; usual time = 6/5 hr = 1 hr 12 min.   Answer : 1 hr 12 min
<result>C</result>
Walking 6/7th of his usual speed, a man is 12 minutes too late. The usual time taken by him to cover that distance is :