The students of a large university in Luzon were studied regarding their hours of sleep at night. The hours of sleep can be modeled as a normal distribution with a mean of 6.9 hours and a standard...

The students of a large university in Luzon were studied regarding their hours of sleep at night. The hours of sleep can be modeled as a normal distribution with a mean of 6.9 hours and a standard deviation of 1.5 hours. Find the 85th percentile of the distribution of hours of sleep.