The average starting salary for this year's graduates at a large university (LU) is $20,000 with a standard deviation of$ 8000. Furthermore, it is known that starting salaries are normally...

The average starting salary for this year's graduates at a large university (LU) is $20,000 with a standard deviation of$ 8000. Furthermore, it is known that starting salaries are normally distributed.

a. What is the probability that a randomly selected LU graduate will have a  starting salary of at least $30400?

b. what is the probability that a randomly selected LU graduate will have a salary of exactly $30400.

c. Individuals with starting salaries of less than $ 15600 receive a low-income tax break. What percentage of the graduate will receive the tax break?

d. If 189 of the recent graduate have salaries of at least $32240, how many students graduated this year from this university?