In a science fair, there are two types of tables that can be used to display the children’s science experiments. At the circular tables, 4 poster boards and 5 participants can fit around the table to cater to 8 guests. At the rectangular tables, 4 poster boards and 4 participants can fit around the table to cater to 12 guests. However, each circular table takes up 15 units of space while each rectangular table takes up 20 units of space. The science fair has must be able to fit at least 500 participants and 300 poster boards. If the science fair has available 1900 units of space, how many of each type of table should be set up to maximize the number of catered guests?