I want to know the answer to the following question:
Travelling to work has been observed to be about how long for a large number of cities over a long period?
All the background I'm provided with is that "However, some aspects of time use are relatively stable over long periods of time, such as the amount of time spent traveling to work, which despite major changes in transport, has been observed to be about 20–30 minutes one-way for a large number of cities over a long period.". Is that enough to answer the question?
Answer: yes