Debbie is borrowing 3 books from her friend who has a collection of 45 books. which of the following expressions represents the number of ways debbie can choose a group of 3 books?
a.p(45, 3)
b.c(45, 3)
b.45!

b.C(45, 3)

Step-by-step explanation:

Given: Debbie is borrowing 3 books from her friend who has a collection of 45 books.

Therefore,  the number of ways Debbie can choose a group of 3 books will be equal to the number of combinations of selecting 3 books from 45 books.

i.e. The number of ways Debbie can choose a group of 3 books=

In this scenario, I'm assuming each question has the value of one point.  Begin by taking 70% of 28 to represent the exact score you need:

0.7(28) = 19.6

You need to get 19.6 points for a 70%.  To calculate the points missed, subtract this from the total points on the test:

28 - 19.6 = 8.4

You can only miss 8.4 points on the test, or no more than 8 questions, to get a grade of 70%.