Running times for 400 meters are Normally distributed for young men between 18 and 30 years of age with a mean of 93 seconds and a standard deviation of 16 seconds. Thus, 99.7% of running times are approximately between

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you can play around with Z table stuff here:

http://davidmlane.com/hyperstat/z_table.html

For this problem, you find that 99.7% of the area lies less than 2.748 ? above the mean.
45 and 141 seconds