Cholesterol levels for women age 20-34 follow an approximately normal distribution with a mean of 185 milligrams per deciliter. Women with cholesterol levels above 220 milligrams have considered to have high cholesterol. About 16% of women fall into this category. What is the standard deviation?

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min