Question

Mrs. Grady surveyed 30 students, 11 of which said they liked basketball, 16 of which said they liked hockey, and 2 of which said they liked both sports.

(a) How many students did not like either sport?
students

(b) How many students liked exactly one of the sports?
students

Answer 1

If 11 like basketball and 16 like hockey, you get a total of 27, but if 2 said both then you don't want to double count them, so a total of 25 students answered. If 25 total students answered but 2 liked both, then 23 only liked one. 

The answer to (a) is 5 students did not like either sport

The answer to (b) is 23 students liked exactly one sport.