11. A 2-mi cab ride costs $4.25. A 7-mi cab ride costs $8.50. Which equation models the cost y of a cab ride that is x miles?

Ateacher wanted to buy a chair, a bookshelf, two tables and a desk. she spent $900 for all five items and the chair and the desk combined 70% of her total. if the bookshelf cost $50, how much did each of the tables cost?