Question

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

Answer 1

Since, there are
`12` boxes of books to put on shelves and each one box has
`31` books.

Therefore, total number of books to put on shelves are:
`12*31 = 372` books

Since, each shelf holds
`18` books.

So, the number of shelf needed are given by: Total number of books divided by the number of books each shelf holds.

i.e.,
`372 / 18 = 20.67`

Therefore, in order to place all the books onto the shelves. There are 21 shelves needed.