A sales representative who visits customers at home finds she sells 0, 1, 2, 3, or 4

Question:

A sales representative who visits customers at home finds she sells 0, 1, 2, 3, or 4 items according to the following frequency distribution.
Items sold Frequency
0..........8
1 ............10
2 ..........3
3 ..........2
4 ..........1
1...........3
Find the probability that she sells the following.
a. Exactly 1 item
b. More than 2 items
c. At least 1 item
d. At most 3 items