at books unlimited, 3 books cost $18. what much would 7 books cost ? how many books could be purchased with $54? show your work. pls help

Respuesta :

First you have to find the unit rate by dividing $18 by 3 books. You get $6 per book. To find the cost of 7 books multiply 7 by $6 and you get $42. To find how many books you can buy with $54 divide 54 by 6 and you get 9 books.