Can someone help me with my questions

Atheater wants to build movable steps that they can use to go on and off the stage. they want the steps to have enough space inside so they can also be used to store props. how much space is inside the steps?

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?

As a salesperson you get $50/day and $3.60/each sales you make. if you want to make $60 in one day, how many sales would you need need to make ? a 3b 4c 5d 6 show work.