Given:
Book club A charges $20 for membership and $2 per book rental.
Book club B charges $10 for membership and $3 per book rental.
To find:
The number of books for which the cost be the same at both book clubs.
Solution:
Let x be the number of books.
Book club A charges $20 for membership and $2 per book rental. So, the total cost is
...(i)
Book club B charges $10 for membership and $3 per book rental. So, the total cost is
...(ii)
Equating (i) and (ii), we get
The total cost is
Therefore, the total cost at both book clubs are same for 10 rental books and that cost is $40.