Walking Distance

In the course of marketing properties, there is this favourite phrase : WALKING DISTANCE TO MRT. That's because proximity to the MRT is so crucial for working class people, who do not drive for whatever reasons, or that they have school-going children who take public transportation.
When we use this term, it's almost common sense that we do not mean a 30-minute walk - a walk that long is great for exercise, moving from shopping complex to shopping complex, but certainly not walking to catch a train - at 30-minutes away, it may make more sense to take a feeder bus.
Well, I had an interesting enquiry - a lady caller wanted me to tell her, exactly how many minutes it would take to walk to the MRT. When I explained that it would depend upon how fast a person walks, she responded : "normal walking speed".
That is really annoying.
I guess it didn't occur to her that what is normal to one person can either be fast or slow for another. There is no moderate speed, because how fast we walk, would also depend upon whether we are late for an appointment, what kind of shoes we are wearing, the weather and the list goes on.
She refused to listen to the rationale. And so I ended the conversation with:
"Sorry, we didn't use a stopwatch to time the distance, therefore, I cannot give you the exact timing".