Answer:
99.7%
Step-by-step explanation:
The 68-95-99.7 rule refers to what percentage of data is contained within ranges a certain distance from the mean.
68% of the data lies within one standard deviation of the mean
95% lies within two standard deviations, and
99.7% lies within three standard deviations.
Our mean here is 600, and our standard deviation is 120, so those ranges would be:
480-720 for 1 standard deviation
360-840 for 2 standard deviations, and
240-960 for 3.
Our given range is 240 to 960, three standard deviations from the mean, so the 68-95-99.7 rule tells us that this range contains 99.7% of the people.
