Books'R'Us is proportional. Bargains'R'Us is not proportional.
Step-by-step explanation:
Susan buys books at two stores. At Books'R'Us, she can buy a book for $1.25 each. At Bargains'R'Us, she made a deal to buy a set of 3 books for $4.00 and a set of 5 books for $5.00.
Book'R'Us is proportional because each book costs a consistent value of $1.25. 0 books is $0. 1 book will be $1.25 and 2 books will be $2.50 and 3 books will be $3.75.
Bargains'R'Us is not proportional because each book has a different price depending on the bargain. Though 0 books is $0, a set of 3 costs $4.00 or $1.34 a book. A set of 5 costs $5.00 or $1 per book. The cost is not consistent or constant. It changes from situation to situation. This is not proportional.
