Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: walking at 5 / 6 th of its usual speed a cab is 12 mnts late . find its usual time to cover the journey ?
60 m
The usual time is 72 minutes.