In a survey of the dining preferences of 110 dormitory students at the end of the spring

Question:

In a survey of the dining preferences of 110 dormitory students at the end of the spring semester, the following facts were discovered about Adam's Lunch (AL), Pizza Tower (PT), and the Dining Hall (DH).
30 liked AL but not PT
21 liked AL only
63 liked AL
58 liked PT
27 liked DH
25 liked PT and AL but not DH
18 liked PT and DH
(a) How many liked PT or DH?
(b) How many liked all three?
(c) How many liked only DH?