90% of students at a university use a backpack, while the rest do not. of all the students, 50% carry their laptops with them and 5% carry neither a backpack nor laptop. what percentage of students carry their laptops and use a backpack?

Explain step-by-step how to simplify -5(2x – 3y + 6z – 10).

What numbers are included in the set of integers? what numbers are not included?

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?