Mr. Graham's business expenses exceeded the company's allowance of $100 when he spent $15 for dinner and $10 for breakfast and paid to stay in a motel overnight. What was the cost of the motel room?

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?