The manager of a concert hall estimates that 500 people attend each classical concert ...

The manager of a concert hall estimates that 500 people attend each classical concert, 900 people attend each jazz concert, and 400 people attend each rock concert. In any given month, the total of the number of classical concerts and the number of jazz concerts may not exceed 11 and the number of rock concerts must be no more than 6. Furthermore, there should be twice as many rock concerts as classical concerts in any given month.

How many of each type of concert should there be in a month in order to maximize attendance? What will that attendance be?