9) A bookstore sold 15 books in 5 days. At
this rate of sales, how many days will it
take the store to sell 21 books?

hii pls help

Respuesta :

1. Find the unit rate

15 books divided by 5 days = 3 books sold per day.

Since we are looking for how many days it would take the store to sell 21 bucks, we could do 21 (amount of books) divided by 3 (how much books is sold in a day).

Therefore, it will take a week / 7 days to sell 21 books.