A sample of fifth-grade classes was studied in the journal article "Predicting Feelings of School Safety for Lower, Middle, and Upper School Students" (Applied Psychologyin Criminal Justice, Vol. 7, Issue 2, pp. 59-76) by R. Bachman et al. One of the variables collected was the class size in terms of student-to-faculty ratio. The student-to-faculty ratios of the 81 fifth grade classes sampled have a mean of 15.83 and a standard deviation of 1.74.

Assuming the variable "student-to-faculty ratios" has a normal distribution, answer the following questions.

1. What percentage of the fifth grade classes contain "student-to-faculty ratios" from 14.09 to 17.57?%
2. 95% of the fifth grade classes contain "student-to-faculty ratios" fromto.
3. How many fifth grade classes contain "student-to-faculty ratios" from 10.61 to 21.05?classes.