There are 12 boxes of books to put on shelves . each box has 31 books. each shelf holds 18 books. kevin estimates he will need 20 shelves for all the books

21 shelves

Step-by-step explanation:

I'm going to guess that you want to know if Kevin is correct in his estimate.

How many books are there is total?

12 boxes * 31 books/box = 372 books in total

Each shelf will hold 18 books so

372 books * [1 shelf /18 books] = 20.6666 shelves.

To be safe unless he wants to stake some of the left over books, he will need 21 shelves. You have to round up for the left over books. 20 shelves is a good estimate, but you will need just one more that has 1/3 of a shelf left over. He can put a picture of his family there.

1.0

step-by-step explanation:

1. sometimes

2. never true

3. sometimes

step-by-step explanation:

these are pretty self explanatory if you know what supp right and com angles are