posted by Anon .
At a distance of 30 m the noise from the engine of an jet has an intensity level of 130 dB.
At this level, you will be in pain and your ears will hurt. That's why this intensity is know as the "pain threshold".
How far do you have to be from a jet (total distance in meters), in order for the noise to drop down in intensity to 69 dB, a level comparable to that of a spoken conversation?