Math

The physical plant at the main campus of a large state university recieves daily requests to replace florecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 57 and a standard deviation of 10. Using the 68-95-99.7 (Empirical) Rule, what is the approximate percentage of lightbulb replacement requests numbering between 57 and 77? The approximate percentage of lightbulb replacement requests numbering between 57 and 77 is %. (Do not enter the percent symbol. )