I need help with this If right

To decrease an amount by 16% what single multiplier would you use

George writes the mixed number as sum and uses the distributive property 1/2.-2/5=1/2-2+2/5=1/2

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?