About 35% of U.S. workers are college graduates. You randomly select 500 U.S. workers and ask them

Question:

About 35% of U.S. workers are college graduates. You randomly select 500 U.S. workers and ask them whether they are college graduates. Find the probability that the number who have graduated from college is
(a) Exactly 175,
(b) No more than 225,
(c) At most 200,
(d) Identify any unusual events.
Explain.