6. where t is the number of years since 1960. determine the estimated world population in the year 2020 since 1960, the growth in world population (in millions) fits the exponential function a(t) 3100e 0.0166t 7. the loudness of sounds is measured in a unit called the decibel. to do this, a very faint sound, called the threshold sound, is assigned an intensity lo. if a particular sound has intensity i, then the decibel rating of this louder sound is given by db rating = 10 find the decibel rating of a human voice if the intensity is 630,957,34410. round to the nearest whole number