The variable, X, has a normal distribution with a mean of 5 and a standard deviation of 3. Calculate

The variable, X, has a normal distribution with a mean of 5
and a standard deviation of 3. Calculate the probability that

The lifespan of car batteries follows a normal distribution
with a mean of 5 years and a standard deviation of 10 months. Calculate (a) the
probability that a car battery lasts more than 6 years (b) the percentage of
batteries that fail before they are 3 years old.