Suppose the probability of a single well hitting oil in one field is 1/15 and in a second field is 1/30. what is the probability that a well in each field will both produce oil?

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?