The serum cholesterol levels in men aged 18 to 24 are normally distributed with a mean of 178.1 and a standard deviation of 40.7. A group of 9 men aged 18 to 24 randomly selected.
1. Find the probability that there are at least 2 men in the group whose serum cholesterol level is at most 230.
2. Suppose 90% of men's serum cholesterol level is less than c. What is the value of c?