Answer: 2.28%
Step-by-step explanation:
Given: An airport find that at the present time, the mean noise level is 103 decibels and the standard deviation is 5.4 decibels.
The distribution of noise levels(x) for all jets during takeoff over the neighborhood has a normal distribution.
The probability that jets have a noise level less than 92.2 decibels when taking off over this neighborhood will be :-

Hence, the percent of these jets have a noise level less than 92.2 decibels when taking off over this neighborhood = 2.28%
It would take her 10 hours.
Explanation: 650 divided by 130 is 5 and 2 hours multiplied by 5 hours is 10 hours. Sorry if I got it wrong, but hoped I helped.