Hi, Can anyone help me on this homework question I have been stuck on this for awhile. Thank you!

Question with last attempt is displayed for your review only A type of battery-operated led lights has a known mean lifetime 7.5 hrs with standard deviation 0.3. Assuming that the lifetimes of these led lights have a nearly symmetric/bell-curve distribution, find the percent (%) of these led lights having lifetime between 6.9 and 7.2 hours. Message instructor about this