11. In which situation is the amount of money earned determined by a proportional relationship? a) A tour guide at the museum was paid a salary of $1,500 for the entire year.

b) A songwriter was paid a different amount for each song she wrote depending on it popularity.

c) A dog walker charged her clients a $10 flat-rate monthly fee plus $5 per walk.

d)An editor charged her clients $1.25 per page for editing.​

Plz heeeeeeelp plz give me the answer

Quick! a survey of 57 customers was taken at a bookstore regarding the types of books purchased. the survey found that 33 customers purchased mysteries, 25 purchased science fiction, 18 purchased romance novels, 12 purchased mysteries and science fiction, 9 purchased mysteries and romance novels, 6 purchased science fiction and romance novels, and 2 purchased all three types of books. a) how many of the customers surveyed purchased only mysteries? b) how many purchased mysteries and science fiction, but not romance novels? c) how many purchased mysteries or science fiction? d) how many purchased mysteries or science fiction, but not romance novels? e) how many purchased exactly two types of books?

Use sigma notation to represent the following series for 9 terms.