elementary statistics
posted by joanne .
The distribution of cholesterol levels in teenage boys is approximately normal with u=170 and o=30. Levels above 200 warrent attention. Find the probability that boy has a cholesterol level greater than 225.

Z = (scoremean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion Related to the Z score you calculate. 
how many seven digit telephone numbers are possible if digits can be repeated?