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:

 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:
[A] 1 hour
[B] 1 hr 12 min
[C] 1 hr 15 min
[D] 1 hr 20 min



ANS: B
Explanation:
New speed = (6/7)of usual speed.
New time = (7/6) of usual time.
Therefore (7/6 of usual time)- (usual time) = (1/5) hr.
=> (1/6 of usual time)= (1/5) hr => usual time = (6/5) hr = 1 hr 12 min.