Ajewelry maker produces necklaces that sell at $85 each. the jewelry maker's costs include $35 in materials for each necklace plus fixed costs of 1650. how many necklaces must the jeweler sell to break even

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?