I hope you can give step by step solution because I'm so stuck on these. thank you.

W8: Exercise 1. A random sample of size 12 is taken from a population which is normally distributed with a mean 38 and variance 12. Find the probability that the sample mean a. is less than 36 b. is not more than 40.5 c. lies between 37.2 and 40.8 [9] 2. A random sample of size 40 is taken from the binomial distribution B(50,0.4). Find the probability that the sample mean a.is more than 19 b.lies between 18.5 and 20.5 [6]