A box of 60 cookies is brought to a class party. It contains 30 chocolate chip cookies, 18 peanut butter cookies; the rest are snickerdoodle. You randomly select cookies, without putting them back in the box. What is the probability that:
a. You randomly select three cookies, but never get a snickerdoodle.
b. You randomly select two cookies and they are the same flavor (meaning either both chocolate chip, both peanut butter or both snickerdoodle)?