What is the average number of people in the world?
As of February, 2014, the world population is about 7.2 billion people
The answer to the question depends on the definition of piano tuner. If you assume the question refers to professional piano tuners only, and includes those professional piano tuners who are not exclusively piano tuners, the number could be approximated as follows: Number of piano tuners in the world = (number of pianos that are periodically tuned in the world / average number of years between tunes for a periodically tuned piano) / average number…
Figure it out. Find out how many people the average car holds and divide that into the number of people in the world. That tells you how many cars you need. Now multiply the number of cars by the average length of a passenger car plus the space between cars. You now have your answer. Of course as soon as you have your answer it is no longer correct as the populating grows every second.