I need this answer in an hour please, be as detailed as possible so I can follow along with: Part A The average starting salary of this year's

I need this answer in an hour please, be as detailed as possible so I can follow along with:

Part A

The average starting salary of this year's graduates of a large university (LU) is $25,000 with a standard deviation of $5,000. Furthermore, it is known that the starting salaries are normally distributed.

1. What is the probability that a randomly selected LU graduate will have a starting salary of at least $31,000?
2. Fill in the blank: 20% of this year's graduates will have a starting salary that is higher than $_____? 

Part B

10 items were randomly selected from a large inventory and 25% of these items are made in Canada.

1. What is the probability that exactly 4 of the 10 items selected are made in Canada? 
2. What is the probability that at most 4 of the 10 items selected are made in Canada?