posted by Alejandra .
The caffeine content of a cup of home-brewed coffee is a normally distributed random variable with a mean of 115 mg with a standard deviation of 20 mg.
(a) What is the probability that a randomly chosen cup of home-brewed coffee will have more than 130 mg of caffeine?
(b) Less than 100 mg?
(c) A very strong cup of tea has a caffeine content of 91 mg. What is the probability that a cup of coffee will have less caffeine than a very strong cup of tea?